| Article: 6519
Newsgroups: rec.sport.golf
From: [email protected] (Dave Tutelman)
Subject: Club Design Article - 0/5
Organization: AT&T Bell Labs - Lincroft, NJ
Date: Sun, 14 Mar 1993 01:38:27 GMT
Well, here it is -- the article I promised on golf club design.
Should generate some good discussions, since some of it is admittedly
controversial. I'll be saving the discussion, and maybe incorporating
some of it in a future posting.
It was longer than I expected: 36 pages in all. Given the amount of work
here (and material I either haven't seen elsewhere or I haven't seen in
an organization I like), I'm considering turning it into a book, and
actually trying to get it published. (Probably won't, but I want to keep
that possibility open.)
For that reason, among others, I have attached a copyright notice to the
article. I'm stating here the terms of the license, which are basically
the same as many "freeware" licenses:
- You may use this article yourself.
- You may make copies of this article for your own use.
- You may give copies to others, provided:
1. You include the entire article, all parts, including this license
notice, and
2. You make no charge for the copy, even to defray your own expenses
in making or shipping the copy.
- You may make an electronic version of the copy available on a bulletin
board or archive site, provided:
1. You include the entire article, all parts, including this license
notice, and
2. You make no charge for the copy, nor for access to the bulletin
board or archive.
I don't think this will hamper anyone from using the article or sharing it
with friends, but it protects my rights to it and prevents others from
making a profit on my work.
That out of the way, here's the first of the six parts.
+-----------------------------------------------------------+
| Dave Tutelman |
| Physical: AT&T Bell Labs, Lincroft, NJ, USA |
| Logical: [email protected] -or- attmail!dtutelman |
| Audible: Work (908) 576-2194 |
| Home (908) 922-9576 |
+-----------------------------------------------------------+
- 1 -
INRODUCTION
Dave Tutelman
Copyright (C) 1993 - All rights reserved
Serves me right for saying that building your own clubs is easy and
rewarding. Immediately I saw a slough of postings and E-mail following one or
more of the following patterns:
"I once made a clone club. It was a real clunker, heavy and clumsy.
I've concluded that all homemade clones (maybe all clones) are
clunkers. I'll only use name brands from now on."
"I bought a club from a custom clubmaker, using the best [popular
model here] shaft and clone clubhead. It came out so light I can't
swing it. What should I do, and how could it have come out badly
with good, expensive components like that?"
"I bought a [brand name, popular model] driver. It's my first
graphite shaft. Now, whenever it's important to get a good drive, I
hit nothing but high slices. What's wrong? I'll never use a
graphite shaft again."
This gave me pause. How come none of these matches my experience with
clubmaking? (I can only remember one "clunker" club I made, and it was one of
my first three.) Have I just been lucky? Am I encouraging fellow netters to
waste their money and time?
I mentally went over the clubs I've made in the past four years, and noticed
something interesting: After my first three clubs (a wedge, a driver, and a
putter), I spent a lot of time poring over catalogs, measuring existing
clubs, and even doing calculations before ordering the components. This
undoubtedly stems from my engineering background and my own tendency to
"design first, then measure twice to cut once."
But I'm convinced that it also warded off the "clunkers". All the clubs since
the first three have generated reactions ranging from "this feels right; my
old clubs didn't" to "this is great; can you make me one like it."
How come? Well, my first consideration was NOT what the club looked like. The
"clones" try to sell themselves on the basis that they look like a popular
model. But I've seen different companies' Ping clone heads that cosmetically
resembled Pings, but differed (from the Ping and among themselves) in the
much more important characteristics like weight and sole shape. No wonder
selecting a club based on looks results in a high percentage of "clunkers".
Instead, I concentrate on finding out as much as I can about the game and the
frame of the golfer for whom I'm making the clubs. I think about what I'm
trying to accomplish, and choose the components accordingly. This may not be
as much fun as making something that looks exactly like a Titleist DCI...
until the golfer gets them to the course. Then the accuracy of cloning the
"look" will matter less than the accuracy of matching the golfer's game and
frame.
- 2 -
This series of articles records the criteria I use in selecting designing
golf clubs. It isn't a step-by-step design method; I don't think that exists.
But if you understand the material here, and apply it to the most critical
characteristics of the clubs you try to build, you're going to make very few
"clunkers".
In the centerfold of the GolfWorks catalog, attached to the order form, is a
form that says, "Planning to buy new clubs? We'll give you a free fitting via
FAX." It then has a half-page questionnaire that they consider sufficient to
make a recommendation about what to look for in a club that matches YOU.
While I wouldn't ask exactly the same questions, I'd like to mention what
they are to start you thinking about what is important in designing a set of
clubs:
- When you hit a poor drive, do you have a specific tendency to:
(top it, sky it, hit it very low, pull it, hook it, push it, slice
it, straight but unsolid hit, very inconsistent, don't know)?
- What is your confidence level with the driver?
- How far does your average drive carry (no roll included)?
(up to 135, 136-170, 171-210, 211-245, 246 and up)
- When you hit a poor iron shot, do you have a specific tendency to:
(same list as driver)?
- What is the longest iron you hit with confidence?
- What best describes the direction you hit with woods and irons?
(Slice, push, straight, pull, hook)
- What is your golf glove size?
- From your own point of view, what do you want from the new clubs?
(Hit the ball higher, hit the ball lower, stop slicing, stop
pushing the ball, stop hooking, stop pulling the ball, hit the ball
straighter, hit the ball longer.)
- Shaft material (preferred, and currently using)?
- What is your current club model, size, and shaft flex?
In my opinion, this is a good starting point. I'd add questions about your
physical measurements, swing plane, how often you play, etc.
Anyway, you should get the idea that this article on the design parameters of
golf clubs will suggest how to match the clubs to the golfer. Ignore the
considerations herein, and you will have your share of "clunkers".
The rest of the articles are:
1. Physical background - reviews a few concepts from physics before we start:
torque, moment of inertia, and what makes a golf ball go far.
2. Swingweight - what it is, how to estimate it from your design, how to
measure it in a finished club, and how to change it.
- 3 -
3. Length - how long should you make the club, and what are the design
problems a nonstandard length gives you?
4. Shaft flex - how to select it, and make sure the finished club reflects
it.
5. Customizing the clubs - given the golfer's game and frame, what features
should the club have?
I hope this information helps you and those who use the clubs you make as
much as it has helped me, my family, and my friends.
- 4 -
1. PHYSICAL BACKGROUND
Dave Tutelman
Copyright (C) 1993 - All rights reserved
Without trying to scare anybody off, there's a little physics that you ought
to know in order to get some intuition for the design principles in the rest
of these postings. In later sections, I'll be trying to cover the design
"rules" so that you could use them without understanding them, but I'm
including this background for those who want to have a feel for their
designs.
The topics covered here are:
- Torque - (or moments or leverage); twisting "forces".
- Moment of Inertia - resisting torque.
- Determinants of Distance - everybody who wants to build a driver ought to
know what makes the ball go farther.
1.1 Torque
Torque is the amount of "twisting force" applied to a body, to turn it around
some axis. The axis is either fixed or assumed fixed for some design purpose.
You may remember it from high school physics as the "moment" of a force on a
lever. In the lever example (which we'll use for a bit here), the fixed axis
is called the lever's "fulcrum". The torque (twisting force, remember?)
produced by any force that acts on the lever is the force TIMES the distance
from the force to the fulcrum.
For instance, suppose I put a 200-gram weight on a lever, at a point 12
inches to the right of the fulcrum. Then the weight will try to turn the
lever clockwise (right side down) with a TORQUE of 2400 inch-grams (200 *
12). Putting more weight on the lever will certainly increase the torque, but
so will moving the original 200 grams further from the fulcrum. If we moved
it out another 12 inches, its clockwise torque would be 4800 inch-grams.
How about a little exercise to really feel what we're talking about here.
- Lay one of your clubs on (or preferably across) a table or workbench,
with the entire grip (and nothing else) hanging over the edge.
- Put your finger on the grip near the butt, and press down until you lift
the clubhead free of the bench. Note what the force you apply feels like.
- Now repeat, but press on the grip about an inch or two from the edge of
the bench. Note how much harder you have to press.
What's going on here is that it takes a certain amount of TORQUE to turn the
club about the fulcrum (the edge of the bench) and lift the clubhead.
Remember that torque is force TIMES distance from the fulcrum. You can apply
that torque by either a small force at the butt or by a much larger force
much closer to the fulcrum.
Torque has a number of interesting applications in golf club design:
- Of course, we're used to reading about the "torque" of a shaft, which is
a complete misnomer. Actually, that rating is an angle (say, 3.5
degrees), not a torque. It is the amount a shaft twists when a standard
- 5 -
amount of torque is applied to it, trying to twist the shaft around its
long axis. The smaller the number, the stiffer the shaft in RESISTING
torque.
- The Center of Gravity (COG) of any body is informally defined as the
"balance point" of the body. A more quantitative definition is that axis
about which the clockwise and counterclockwise torques (due to the body's
own weight) balance exactly. The informal definition is easier to measure
in a finished club, but the formal definition is the way you compute the
COG of something you're designing.
- Swingweight is a torque, too. It's the torque provided by the weight of
the whole club, about an axis near the grip. As such it measures how much
pressure (counter-torque) you have to apply to the grip to swing (turn)
the club about the axis. Note that, since the head is further from the
grip than the shaft, a gram of head weight contributes more to
swingweight (torque) than a gram of shaft weight.
Ironic, isn't it, that the only example that calls itself "torque" isn't
really torque at all, but rather the twisting motion resulting from torque
(called "torsion", not torque).
1.2 Moment of Inertia
When you hit something on its COG, you move it straight away from the point
where you hit it. But if you hit it off its COG, it will twist. Let's verify
that with another little experiment:
- Hang a wire hanger from a finger of your left hand. Its COG will be right
below the finger from which it's hanging.
- Tap it with a finger of your right hand, on the middle of the long
horizontal wire (i.e.- right beneath the COG). Note that it swings back
and forth, but it doesn't turn about its vertical axis.
- Stop it from swinging. Now tap it with the same finger, but just an inch
or so from the end of the hanger. Note how most of the energy from the
tap goes into turning the hanger rather than swinging it.
The reason for the behavior stems from Newton's original observation that "a
mass at rest tends to remain at rest." In particular, the center of mass
(another name for the COG) tends to remain in one place unless prodded. If
you hit it with a force that doesn't go through the COG, the body will just
turn, allowing it to respond to the force without moving the COG any more
than it has to.
Remember torque? Think of the wire hanger as a lever. The COG, which wants
to remain in one place, is the fulcrum for that brief dynamic moment before
anything moves. And therefore the force applied when you tap the hanger is a
torque around that fulcrum. The farther from the fulcrum (COG) you tap it,
the more it wants to twist (rather than swing).
OK, so how much will the hanger twist in response to an off-center tap? We
know mass has an "inertia" that makes it resist a force that wants to move
it. (The famous equation "F=ma" means that the higher the mass the more force
it will take to accelerate it a certain amount.) Well mass has a "rotational
inertia" as well; the higher this rotational inertia, the more torque it will
take to produce a certain amount of rotational (or "angular") acceleration.
The rotational inertia is called the "Moment of Inertia".
- 6 -
As you might expect, the further we place the mass from the COG the more
effective it is in resisting torque. If your intuition doesn't tell you this,
it's time for another experiment.
- Get two identical wire hangers and four identical "weights" (small
objects considerably heavier than the hangers, but still light enough so
you can attach them to the hangers with, say, masking tape).
- On hanger #1, tape two weights to the horizontal wire as close to the
center as possible.
- On hanger #2, tape two weights to the horizontal wire, as far from the
center as possible. One weight should be near each tip.
- Repeat the previous experiment with both hangers, but note how
"enthusiastically" each hanger swings or turns in response to the same
strength of tap.
The two hangers are exactly the same mass, and they should swing identically
in response to tapping the center of the hanger. But, in response to an
off-center tap, hanger #1 will twist much faster than hanger #2. That's
because the weights far from the axis of rotation contribute a lot more to
the moment of inertia than do weights near the axis.
Quantitatively, the distance between weight and the axis of rotation is even
more significant in computing moment of inertia than it was in computing
torque. Whereas the torque of each force is the force times the distance to
the axis, the moment of inertia of each grain of mass is its mass times the
SQUARE of the distance to the axis.
OK, time for a golf application. Consider two putter heads with identical
weights and blade lengths. Head #1 is a simple uniform blade, while head #2
has all its weight at the heel and toe.
- Head #2 has a much higher moment of inertia than head #1, because all its
weight is as far as it can get from the COG. In fact, the moment of
inertia of a pure heel-toe weighted putter is three times that of a
blade, even though their total weight is the same.
- Roughly speaking, the COG is the "sweet spot" of the head. Hit the ball
there and you get a nice straight putt.
- If you hit the ball off-center, the putter will twist and your putt will
go off-line. The higher the moment of inertia of the putter head, the
less it will twist and the closer to the intended line your putt will go.
Conclusion: a heel-toe weighted putter head with its higher moment of inertia
is more forgiving of off-center hits than a blade. Another way of saying this
is that head #2 has a "larger sweet spot".
Now let's talk about cavity-back irons. Clubhead manufacturers talk about the
cavity making the sweet spot bigger. Now we're in a position to understand
what's REALLY going on. It's not that the cavity is magic, but that it allows
all the weight of the clubhead to be moved to the edge of the face. This is
called "peripheral weighting", and (just as we saw with the putters) it
dramatically increases the moment of inertia of the head. And just as with
the putters, this means that the head twists less when you don't meet the
ball right on the sweet spot. That's why the club is more forgiving of
off-center hits. It ain't the cavity at all; it's all the steel they dug out
of the cavity and moved to the periphery.
This also explains why metalwoods are more forgiving than wooden woods of the
same weight. The woods have their mass distributed more or less uniformly
throughout the head, while the metalwoods are hollow shells (because steel is
- 7 -
much heavier than wood). Can you say "peripheral weighting"? I knew you
could.
1.3 Determinants of Distance
Here are a few rules of thumb on how the grossest measurements of a club
affect the distance the ball will travel. I've seen them in a number of
places and they make sense, but the only reference I still have for them is a
June 1992 posting by Sean D. O'Neil reporting on a talk by James Paul
(founder of Airflow Research).
1. Holding everything else constant, distance is a strong positive function
of clubhead speed. (I.e.- distance increases markedly with clubhead
speed.)
2. Clubhead speed is a strong negative function of swingweight. (I.e.-
clubhead speed decreases markedly as swingweight increases.)
3. For a given clubhead speed, distance is a weak positive function of
swingweight. (I.e.- if you can get the clubhead speed in spite of the
swingweight, the extra clubhead mass will increase distance slightly.)
These rules of thumb are consistent with the Golfsmith "philosophy" of
lighter weight for more distance. For instance, quoting from the 1993
Golfsmith catalog:
"Two basic facts about golf clubs and the swing:
1) Greater clubhead speed results in greater distance.
2) Lighter weight clubs permit greater clubhead speed.
Our relatively simple cause-effect sequence was confirmed for us by
USGA Technical Director Frank Thomas. If a club is shafted with
graphite 'lighter than steel by two ounces, then all else being
equal, clubhead velocity will increase by up to three feet per
second -- which will result in approximately five yards increase in
distance.'"
This is completely consistent with the rules above.
- 8 -
2. SWINGWEIGHT
Dave Tutelman
Copyright (C) 1993 - All rights reserved
2.1 What Is It, And Why Do We Care?
Simply put, Swingweight is the sum of torques due to the weight of the club,
measured about a fulcrum 14" from the butt. (We'll get back to that 14" in a
second.) It is intended as a measure of how heavy the club "feels" as you
swing it. It is not the same as the simple (or static) weight of the club;
indeed, there are ways to reduce the swingweight that actually increase the
static weight.
Two things happen as you increase swingweight:
- The club feels heavier swinging, more resistant to the torque your hands
apply during the swing.
- The clubhead travels slower at impact, since the torque you're applying
doesn't accelerate the club as much.
Remember that we want to maximize clubhead speed when designing our club, in
order to maximize distance. (This was covered in the previous section.) Thus
we come to the following design rules for choosing a swingweight:
1. Find the range of swingweight for which your swing feels comfortable and,
more important, controlled and repeatable.
2. Design the club for the lower end of that range, so you get the best
distance out of the club.
I believe in these rules, but not everybody does. In particular, there's a
philosophical debate between Ralph Maltby of GolfWorks and Carl Paul of
Golfsmith about the significance of swingweight. Maltby's position is that
you want to engineer swingweight to a gnat's eyebrow, and the GolfWorks
clubheads reflect this belief. Almost every club (including many of the irons
and even a few putters) have weight ports to trim the swingweight. Some of
his newer driver heads come with three setscrews for the soleplate, each a
different size so as to be a swingweight point apart; pick the one that gives
the best swingweight for you and epoxy it in place.
Golfsmith, on the other hand, says in their catalog,
"We encourage clubmakers to resist the temptation to increase
clubhead weight in order to bring the shaft up to an arbitrary
'standard' (typically D-0 or thereabouts). 'Feel' in the swing is
extremely important. Weight added to achieve feel may be desirable.
Weight added for 'higher swingweight' is not. Remember that head
speed has a much greater influence on distance than head weight."
Like GolfWorks, Golfsmith puts their money where their mouth is. Their iron
heads tend to be among the lightest on the market. Unfortunately, they
haven't been as consistent with their driver heads, offering some as
"graphite weighted" -- that is, heavier heads to allow for the use of lighter
graphite shafts.
OK, so far we have a definition for swingweight, but no usable units to
- 9 -
measure them. They are measured on a funny set of "swingweight points", going
from a very light of A-0 to a very heavy of G-9. Each letter has numbers
ranging from 0 to 9; each number is a "swingweight point". The vast majority
of clubs are within 10 points of D-0 (I've never knowingly seen one outside
this range.) Generally women's clubs are swingweighted in the low-mid "C"s,
and men's in the low "D"s. But use whatever you feel comfortable with. For
distance, use the lowest you feel comfortable with.
Now for a brief digression into physics before we continue with the design
issues. This is NOT required reading, only some puzzling points for the
engineers among my readers.
- Why take the moments about a fulcrum 14" from the butt? Why not AT the
butt, or 4" from the butt (approximating the middle of where the hands
grip the club)? I honestly have no idea. At least one writer, Carl Paul,
says the definition is 12", but the swingweight scales sold by his shop
(as well as the others) have the fulcrum at 14".
- Why torque? Why not moment of inertia, which is the resistance to
accelerating in the presence of torque? Again, I have no idea.
I just have to assume that this time-honored measurement has been empirically
validated to give a measure such that, if two clubs have the same
swingweight, they will "feel" the same to swing even if they have quite
different dimensions. Not everyone is prepared to accept this assumption; in
the October/December issue of Golfsmith's Clubmaker magazine, Bub Bush of
True Temper trashes swingweight as a meaningful indicator. So it's not a
closed case. However, it's a measurement that most clubmakers find useful,
and there isn't a good substitute for it today.
2.2 Predicting Swingweight - Sensitiivity Tables
OK, so a swingweight of D-0 is sort of a "nominal standard", but shouldn't be
a religious issue. But how do I estimate in advance the swingweight of a club
for which I haven't even bought the components?
For instance, suppose I want to try a "lighter and longer" driver (the Yonex
principle). How much lighter gives how much longer, with the same
swingweight? Questions like this come up all the time in clubmaking. The
start of my answer came in the form of a data point and some "sensitivities"
in the Golfsmith Clubmaker, March/April 1992.
DATA POINT:
Driver with 200 gram head
128 gram (standard) shaft
43" (standard) length
Swingweight = D0.
SENSITIVITY:
One inch of length is worth 6 swingweight points.
Four extra grams of weight in the butt of the club REDUCES the
swingweight by one point.
I found a few more sensitivities in other books and catalogs. Then I dusted
off the Physics and Calc 101 books, and came up with a set of conversion and
sensitivity tables, and finally an approximate formula for swingweight.
- 10 -
The sensitivity tables are, IMHO, more useful than the formula for absolute
swingweight. They are also probably more accurate. But I present both as
potentially useful to someone trying to estimate the swingweight of a club
being designed. The tables are more useful in knowing how much to "tweak" a
design to achieve a swingweight that you know (from experience) feels good to
the golfer who will play with the club.
Now the tables.
The first set of numbers reflects the sensitivity of swingweight to (1) head
weight, (2) shaft weight, and (3) length. Using these numbers, I've computed
the tradeoff factors among (1), (2), and (3).
CLUB
=====================================
Driver 4-Iron Wedge
Head wt. 200 g 250 g 300 g
Shaft wt. 100 g 100 g 100 g
Length 43 " 38 " 35 "
-------- -------- -----
Grams of head wt. per SW point 1.6 g 1.9 g 2.2 g
Grams of shaft wt. per SW point 5.3 g 7 g 9 g
Inch of length per SW point 1/5 " 1/6 " 1/7 "
Head wt vs. Shaft wt. (constant SW) 3.3 3.7 4.2
Head wt vs. Length (constant SW) 8 g/in 12 g/in 16 g/in
Shaft wt vs. Length (constant SW) 26 g/in 43 g/in 64 g/in
=======================================
Two other sensitivities that don't need a table:
- 4 grams of weight at the butt REDUCES swingweight 1 point.
- 6 grams of weight in the grip REDUCES swingweight 1 point.
(Note that the vast majority of grips are within a few grams of 50 gm.)
2.3 Design Examples
What do these tables mean? Here are a few examples (the first being my
original question: lighter and longer):
- I'm going to get a head that's 4 grams lighter than "average" and a shaft
that's 24 grams lighter than "average". How much longer can I make the
club, and keep the same swingweight as an "average" driver?
Head wt vs. length = 8 g/in.
Thus 4g off the head gives us an extra 1/2".
Shaft wt vs. length = 26 g/in.
Thus 24g off the shaft gives us almost an extra 1".
Net is almost an inch and a half extra.
- 11 -
- My clubs are the right length, but they feel too light. I'd like to get
an extra 2 swingweight points on my irons. How much weight should I add
to the head?
Head wt per SW point = 1.9g for a 4-iron,
to 2.2g for a wedge.
Thus, to go up by TWO SW points,
add 3.6g to a 2-iron (a little under 2*1.9),
add 4.4g to a wedge (2*2.2),
and scale the weight added to the clubs between.
Realistically, this means "add 4 grams to each club".
- I know from experience that I can swing a C-8 driver consistently, but I
get a little wild with a lighter swingweight. I've decided to make a new
driver from a head I like that weighs 205 grams. I'd like as long a shaft
as possible, but no shorter than the standard 43"; I'd also like NOT to
spend a bundle on the shaft, so a super-stiff super-light shaft is out of
the question. Just for laughs, let's say the shaft has to cost under $35
and torque under 4 degrees. It should have a mid-bend point and a stiff
flex.
Remember the "standard D-O" data point:
200 gram head
128 gram (standard-weight steel) shaft
43" (standard) length
Let's use it as a starting point, and count swingweight points
different from it.
C-8 Standard is D-0, we need to lose 2 pts.
205 gm. Standard is 200, we need to lose 3 pts.
43" Let's start with this, and add length
only if we find we can.
So we need to save 5 swingweight points, and our first tool is
to lighten the shaft.
From the tables, we need 5.3 * 5 = 26 grams.
Thus the shaft has to be under 128 - 26 = 102 grams.
This is easy; a few name-brand shafts that meet spec are:
Aldila HM-30 $25 85 gm. 3.6 deg
Grafalloy ASW $35 85 gm. 3.0 deg
Grafalloy Sen.Pro $29 90 gm. 3.5 deg
Kunnan K2 $28 100 gm. 3.6 deg
TrueTemper Gold+ $10 104 gm. 2.5 deg
The obvious choices are the Gold Plus and the HM-30
(Gold Plus included assuming it's OK to be a couple of
grams overweight on the shaft; I'm sure it is.)
With the Gold Plus, we get no extra shaft length.
With the HM-30, we have 102 - 85 = 17 grams to play with.
From the table, we can get another 17/26 inch (which we'll
round to 5/8").
2.4 Pedicting Swingweight - Equation
Here's an equation derived from the definition, but with a couple of
constants derived from the sensitivities and data points.
- 12 -
L*(H + S/2) - 14*(H + S + G + B) + 4G
SW = - 125
50
Where:
SW = Swingweight with respect to D-0. That is:
if SW = 2, then swingweight is D-2.
if SW = -4, then swingweight is C-6.
L = nominal club Length (inches)
H = Head weight (grams)
S = Shaft weight (grams)
G = Grip weight (grams)
B = extra Butt weight (grams)
The equation has three components, the numerator (an algebraic expression),
the denominator (the number "50"), and the offset (the number "125"). Here's
how they were derived:
Numerator - Was determined from the definition and freshman physics. Plus a
couple of measurements: I checked a few shafts that were lying around,
and verified that their center of gravity was within an inch of the
center of the shaft in each case. Then I measured a bunch of grips,
and all their COGs were within a quarter inch of 4" from the butt. At
this point I'd have been done with it, except that the definition gave
no units, and I had to fit the answer into the swingweight points
scale.
"50" Was determined from the sensitivities. The 10 data points I have gave
values between 48 and 51, so I'm pretty confident about it.
"125" Simply shifts the scaled moment to give the swingweight values for the
few clubs for which I had data. This is the least certain number in
the formula.
This formula gives swingweights and sensitivities consistent with all the
data points I have. Since they're all in the middle-C to middle-D range, I
can only speak to this range. However, if you're swinging a club too much
outside this range, you're an oddity anyway.
Formulas like this are easy to use, and easy to abuse. Remember that, while
they give a reasonable starting point, you REALLY have to start by knowing
what swingweight is needed by this particular golfer. And that can only be
determined from that golfer's experience. Generally, I'm much more
comfortable with sensitivity analyses based on clubs that are known to be
right (or specifically too heavy or too light) for the golfer in question.
2.5 Measuring Swingweight
If you're going to base your design on existing clubs the golfer has used,
you'll need some way to measure the swingweight of those clubs. The best way
is a swingweight scale, a balance that holds the club by the butt and
balances on a fulcrum 14" from the butt. This is a direct-from-the-definition
measurement of swingweight. Unfortunately, a swingweight scale costs a
non-trivial amount of money, unless you do a lot of clubmaking. Ping makes a
- 13 -
swingweight-only device for $40; more versatile scales (swingweight and
static weight) run $50 - $140.
So is there another way to measure swingweight? If you have a GOOD postal
scale that measures in grams or ounces, you can use it for swingweight. But
you have to take pains to be precise; remember:
- A 0.1 ounce (3 gram) error in weight will result in one swingweight point
of error in the result.
- A 1/8" error in position of the COG will result in one swingweight point
of error in the result.
This should give you some idea of just how good your scale has to be. (I
don't own one good enough for this purpose.)
Having covered that caveat, here's the method. (My thanks to Rich G. Ciccotti
for pointing out this method from Ralph Maltby's book.)
1. Measure the distance of the balance point of the club from the grip end
(in inches).
2. Subtract 14" from the result, and multiply it by the club's total weight
in ounces or grams. The result is the torque (in inch-grams or
inch-ounces) about an axis 14" from the butt, the base definition of
swingweight.
3. Use the following table to convert to the swingweight point scale:
Swingweight Inch-ounces Inch-grams
C-0 196 5600
C-1 197.75 5650
C-2 199.5 5700
C-3 201.25 5750
C-4 203 5800
-
C-5 204.75 5850
C-6 206.5 5900
C-7 208.25 5950
C-8 210 6000
C-9 211.75 6050
-
D-0 213.5 6100
D-1 215.25 6150
D-2 217 6200
D-3 218.75 6250
D-4 220.5 6300
-
D-5 222.25 6350
D-6 224 6400
D-7 225.75 6450
D-8 227.5 6500
D-9 229.25 6550
E-0 231 6600
The next section covers choosing the length of club. Since swingweight is
intimately tied to length, we'll need to use the information from this
section as an important part of the design.
- 14 -
2.6 Altering Swingweight
We'll close the section on swingweight with an important practical aspect.
Let's say you have picked the components you need, and the swingweight is
just wrong. You can't go to a heavier/lighter shaft or clubhead; the reason
might be as simple as you're starting with an already completed (or
store-bought) club. What do you do to increase or decrease the swingweight.
Increasing swingweight:
From the definition, we increase swingweight by adding weight more than
14" from the butt or subtracting weight less than 14" from the butt.
Since it's hard to subtract weight from a finished club, we'll have to
add. In order to minimize the weight gain for a particular swingweight
gain, we'll add it as far as we can from the butt, at the clubhead. How
do we do this in practice?
- The best way is inside the clubhead, if that's physically possible.
Most woods and metalwoods either have weight ports or at least have
room for you to make one. A few irons also have them (including many
models from GolfWorks, which believes this to be an important
adjustment). If your club has a weight port, you can increase the
swingweight with lead (discs, powder, or shot) and epoxy to hold it
in place.
If your wood doesn't have a weight port, you can make one. The
technique of making a weight port is slightly different for woods and
metalwoods. With woods, you just have to remove the soleplate and you
can do the obvious woodworking to hollow out an area and fill it with
lead and epoxy. Then replace the soleplate. (Check a repair book for
the ins and outs of removing and replacing soleplates.)
With metalwoods, drill into the hollow body with a hole that you can
thread for a hex-socket setscrew. Put a lead/epoxy "paste" mixture
into the hole, and seal it with the setscrew.
- If your clubhead doesn't have a weight port and you can't or won't
add one, add the weight with lead tape on the clubhead itself. The
best place to put the tape is somewhere that doesn't greatly affect
the placement of the COG of the head. Note that this implies adding
tape on two diametrically opposite sides of the clubhead, with the
COG on the line connecting them. If you can do this at the heel and
toe of the club, you'll also be increasing the peripheral weighting,
thus making the sweet spot bigger.
If you can't or won't split the tape across the COG, the least
damaging addition is to move the COG straight away from the face of
the club; in other words, put the tape on the back of the clubhead.
An iron the blade is so thin that the effect on COG is negligible;
even with a wood, the effect on hitting is minimal.
Putting tape on the top or bottom of the clubhead will move the COG
up or down. Be sure you want the effect you're going to get.
I have heard a number of people complain that they don't like lead
tape because it's "ugly". The best I can do here is to point out
relevant classic quotes:
- 15 -
- "Beauty is as beauty does." (William Shakespeare [?], poet.)
- "Form follows function." (Walter Gropius [?], architect.)
- "When you hit the ball, you'll forget what it looks like."
(Karsten Solheim, describing his incredibly ugly Ping Zing.)
{ Hey, folks, a little help here, please. I'm trying to make deadline
(promised it this weekend), and we've got a blizzard outside so I
can't go to the library and check the references in Bartlett's. I'm
not sure of any of the above. The architect might well have been
Frank Lloyd Wright instead. Even Karsten might have been brother John
Solheim. Anybody know for sure? I'll check the first two at the
library Monday. }
- Some still advocate putting weight at the tip of the shaft inside the
hosel. This is really a bad idea, for a few reasons:
- The weight is added in one place, a considerable distance from
the COG of the head. This moves the COG (and, very likely, the
sweet spot) toward the heel and probably upward. The result is
that hits in the middle of the face with go toward the right and
not as high as they should.
- There have also been reports of rattles inside the shaft, if any
of the weighting material breaks free under usage. (This is also
a danger in adding weight at a weight port, if the epoxy isn't
used properly.)
Decreasing swingweight:
From the definition, we decrease swingweight by subtracting weight more
than 14" from the butt or adding weight less than 14" from the butt.
Since it's hard to subtract weight from a finished club, we'll have to
add. In order to minimize the weight gain, we'll add it right at the
butt, where we need 4 grams per swingweight point. How do we do this in
practice?
- Golfsmith sells a plastic butt insert which is a cup into which you
can glue or melt lead. If you can carve or bend the right amount of
lead into the right shape to stuff into this insert, you've won the
game. If not, you might want to try "pouring" lead (or a lead/epoxy
paste) into the cup to fill it completely.
While epoxying is a technology familiar to every clubmaker, we
shouldn't automatically be scared off by the thought of melting lead
into a mold like this. It's easier than you think, and gives a much
higher-density weight. I've never tried it with pure lead (which is
what I think you'd get from golf component vendors), but I've used
other lead-heavy materials that melt easily. Consider the following
table.
Material Specific Melting
Gravity Point
Pure Lead 11 326 C
50-50 Solder (Pb,Sn) 9 220 C
Wood's metal (Pb,Bi) 10 150 C
Lead/epoxy (50-50) 6 ---
I've used solder or Wood's metal (melted into a plastic mold with a
soldering iron) to make custom weights very easily. I'm not sure
where to get Woods metal these days, but I got it at model shops
- 16 -
years ago. (Model railroad equipment frequently needs compact weight
added.) Solder, of course, is very easy to obtain and use, and still
much heavier than a 50-50 lead/epoxy slurry.
- Another product is the "Enforcer Grip", which has long been sold by
Golf Day and now appears in the 1993 Golfsmith catalog. It
incorporates 50 grams of zinc in the butt of the grip, and sells for
$5 apiece. (50 grams is a LOT of weight; it's worth 12 swingweight
points.)
- Another product is the brass plug weight available from Hireko. I
don't recall seeing anything bigger than 7 grams. (Note that a lot of
vendors sell weights fitted to the TIP of the shaft to INCREASE
swingweight; be sure you get weights the right size for the butt.)
- 17 -
3. CLUB LENGTH
Dave Tutelman
Copyright (C) 1993 - All rights reserved
Although we haven't covered it first, one of the first questions that you
must answer in designing a club is its length. In this section, we'll address
the design issues relating to length, specifically:
- Measuring the length of a club.
- Choosing the length of the club.
- Simultaneously specifying length and swingweight.
- Other length-related effects, such as flex.
3.1 Measuring Length
The length of a club is defined as the distance from the butt of the club to
the point where the shaft (or its extension) intersects the base of the sole.
Frankly, I have a lot of trouble with using this as a working definition,
because:
- To be useful, length must somehow be related to the sole right under the
"sweet spot", because that's where the club strikes the ground.
- Because clubheads vary markedly in their "camber" (the curve of the
sole), the intersection of the shaft and the sole may be right near the
ground or considerably above it. Consider the following "ASCII-graphics"
diagram:
No-camber sole High-camber sole
/ /
-----_____ / -----_____ /
| -----___/ | -----___/
| / | /
| / |__ __/
|_______________/ ---______---
For the no-camber sole, the intersection of shaft and sole is right on
the ground. But for the high-camber sole, the intersection is
considerably above the ground, resulting in effectively a longer club for
the same nominal length.
For this reason, I believe that the proper measurement of club length is from
the butt to the point where the shaft meets the line tangent to the sole
where it meets the ground in a normal address. Since this is even harder to
measure than it is to parse the above definition, I prefer to measure my
clubs by comparison with a reference "standard" club.
I keep around my workshop an old 5-iron and an old driver (both with very
little camber) that I have measured carefully so I know exactly how long they
are. When I need to measure an iron, I take the "standard" five iron and lay
it on my workbench with the blade hanging over the edge and the shaft
perpendicular to the edge. Then I lay the iron to be measured next to it. I
use a ruler to connect the soles of the two clubs directly beneath their
- 18 -
sweet spots, and slide the clubs around until the ruler is parallel to the
edge. (That is, the soles under the sweet spots are the same distance from
the edge.) Then I measure the butt of the unknown club by comparison with the
butt of the "standard" club.
When I measure a wood, I use the "standard" driver instead of the "standard"
5-iron.
3.2 Choosing Length
It's all very nice to know how to measure a club, but it doesn't do us much
good unless we know what we want the measurement to be. Let's start with the
nominal club lengths for a standard men's set. The following table agrees
with the recommendations from Golfsmith, GolfWorks, and numerous books:
Club Number Iron Length Wood Length
1 39.5" 43"
2 39" 42.5"
3 38.5" 42"
4 38" 41.5"
5 37.5" 41"
6 37" 40.5"
7 36.5" 40"
8 36"
9, PW, SW 35.5"
The nominal women's set is one inch shorter for each club.
According to Carl Paul in Golfsmith's "Golf Clubs - Design and Repair", the
best way to design the length for any particular golfer is ...
"... by measuring the golfer's 'hand height'. This is accomplished
by measuring the distance from the golfer's fingertips to the floor
while he stands erect with arms hanging straight by his side.
Standard clublengths are based on the average 'hand height' of 27
inches for men. A general rule of thumb in determining proper
shaft length is to increase or decrease the club length by 1/4 to
1/2 inch for each full inch of 'hand height' over or under the 27
inch average."
Geometry says that changing club length by only 1/2" per inch of hand height
isn't enough. My own calculations indicate that you want about a one-to-one
ratio; that is, add or subtract an inch of club length for each inch of hand
height. Moreover, I know at least one rather tall person who didn't feel
comfortable with his clubs until they were increased to a full one-to-one to
his hand height. Anyway, now you're heard Carl Paul's opinion and mine;
you're free to develop your own. ("One nice thing about standards is there
are so many of them to choose from." - anonymous engineer.)
There are a few more considerations in choosing a length.
- The golfer may have an unusually upright swing plane, or an unusually
flat one. If you're dealing with this case, you'll need to get clubheads
with an upright or flat lie angle, then compensate by decreasing or
increasing club length.
- 19 -
A rule of thumb is that each degree flatter lie calls for about a 3/8"
longer club. (Given the variation in club lies and lengths, this amount
might be as low as 5/16" and as high as 1/2", but 3/8" is a good design
estimate.)
- Yonex drivers get their bragged-about distance by building drivers as
much as two inches longer than normal. The dangers of this approach are
excessive swingweight slowing down the clubhead more than the extra
length speeds it up, and the fact that only a good, grooved swing can
control the extra length. If you can overcome these problems, it may well
be worthwhile to build your driver overlength; I've had considerable
success with this.
Remember that the extra length must be accommodated by the golfer's
swing. If he/she isn't tall enough so that the extra length is "right"
for the hand height, remember to flatten the lie by enough to compensate.
BTW, this implies (accurately) that, in order to use the overlength
driver, the golfer will have to be able to control a flatter swing than
usual.
For all these reasons, I wouldn't try this approach for any club but the
driver (where the golfer can tee it up to allow for a little error in
accuracy of the swing).
3.3 Coping with Swingweight
OK, so you've decided what length club you need to build.
From a completely different set of considerations (see previous section on
Swingweight), you've decided what swingweight they need to be.
All that remains now is to choose a compatible set of components from the
catalog and build the clubs. Right? Well, maybe. Swingweight and length are
very highly interdependent. If you are making rather long (or short) clubs,
or you like a particular shaft or clubhead with nonstandard weight, you may
need to take some strong measures to get both the length and the swingweight
you need.
I'll focus on the case of long clubs, because that's where I've most
frequently found a challenge in designing to both the right length and
swingweight. Consider the problem of designing a set of irons for my son,
who is very tall and requires clubs 1.5" over a nominal men's set. However,
I don't want to give him anything that swings heavy. I'd like to limit it to
no more than a D-0, and a bit less if possible. His swing calls for an "R" or
soft "S" flex.
We'll work the problem for a 5-iron; I advise starting with a middle iron,
because the solution that works for that club usually can be applied equally
well to the longer and shorter irons. (This principle isn't as applicable
when working with woods because most bags don't have a lot of them, and the
driver is frequently designed quite differently from the others.)
- 20 -
Start with a "standard" sort of 5-iron:
"Usual" clubhead (say an Acer) 256 grams
True Temper Dynamic shaft 124 grams
"Standard" length for men's 5 37.5 inches
===========
Gives a swingweight of . . . . . D-0
No surprise that "standard" components will give a "standard" swingweight.
But, when we add 1.5 inches to the length, the swingweight jumps to D-9.
(Check with the sensitivity tables; 6 swingweight points per inch.) So we
have to do things to reduce the swingweight by at least 9 points. Let's look
at the different ways we could accomplish the design:
Lighter Clubhead - This is the first approach that comes to mind, because
weight at the clubhead is a very strong determinant of swingweight. (If we
were trying to increase swingweight instead of decreasing it, adding
weight to the clubhead is THE time-honored way of doing it.)
Unfortunately, there isn't too much available in this department. The
Golfsmith heads and many Golfworks heads are down to 253 grams for the
5-iron, but there's almost nothing on the market any lighter.
Looking at the swingweight tables for cross-sensitivity, we see that
saving 3 grams of head weight saves 2 swingweight points. We'd be down to
D-7. Let's do it!
Lighter Shaft - We've saved all we can at the clubhead, where saving a gram
really buys something. It takes 7 grams in the shaft to save a
swingweight point. The Dynamic Lite shaft (still under $5 and 113 grams)
saves about 1.5 points. Even if we go to a very lightweight steel shaft
(like the Gold Plus at $10), we're only going to save 21 grams (3
swingweight points). This would get us to D-4.
Trying to get any more out of the shaft weight could get expensive. It
means going to graphite, and for irons I'd want a fairly low torque
graphite shaft (under 3.5 degrees). We're talking over $25 a club for a
name brand and at least $19 for most house brands. Hireko has one for
$12.50 that would save another 3 swingweight points; 3.5 degree torque,
but unfortunately a low bend point. (More about bend point in a later
section.)
Let's go with Gold Plus at D-4.
Upright Lie - We can't save any more swingweight by reducing weight, but
maybe we can reduce the length. Yeah, I know we said 1.5" long but....
A lot of tall players learned their swing before they got a set of clubs
built for their height. Those that did tend to have a rather upright swing
plane. That means we already should have been thinking about an upright
lie for them, but now we have additional motive. Remember that each degree
of lie is worth 3/8". If we can get the club two degrees more upright, we
can shorten the club 3/4" (which, the table tells us, saves 4.5
swingweight points -- we're there!)
Be very careful with the mechanics of going to an upright lie. The things
to try, in order, are:
- 21 -
1. Buy a clubhead that comes in an upright lie. Quite a few models do.
(That's what I eventually did for my son.)
2. If your clubhead is 18-8 ("surgical") stainless steel, bend it to lie.
(You can also pay a shop to do it. The last time I did, it cost $3 a
club.)
3. If your clubhead is 431 stainless steel, it can't be bent any more
than 2 degrees. If I had to face this, I'd pay a shop to do it
ver-r-r-ry carefully, and try to get them to guarantee the job in
advance.
4. If your clubhead is 17-4 stainless steel, it can't be bent without
cracking. Proceed to the next strategy.
Butt Weight - I consider this a somewhat hokey way to take advantage of the
mathematics rather than the spirit of swingweight, but there are products
that insist it works not only on the mathematical definition but on
clubhead speed as well. The only explanation I've seen that makes any
sense to me is that the weight tends to slow down the motion of the hands
but not their release, so you can still release the too-heavy clubhead at
the right point in the swing.
If this really is the effect at work, it's a slightly risky one that
depends on having a decent swing to begin with:
- If your swing is good and your only problem with the club is that you
can't get this high-swingweight club through the ball in time, this
should help.
- On the other hand, if you "cast the clubhead" (uncock your wrists too
early in the swing), this could make it worse.
Getting back to our design problem, we add 16 grams at the butt to lose
the required 4 swingweight points. The mechanics of adding weight to the
butt were discussed earlier in the section on swingweight.
3.4 Other Length-Related Effects
Flex - As we'll see in the next section, the effective flex of a longer shaft
is softer. Thus we need to order a stiffer flex of shaft if we build it
longer (and vice versa for a shorter than normal club). I'd estimate the
change at about 1/2 flex grade per inch. That is, if you're making a 2"
overlong driver and you usually take an "R" flex, order the shaft in "S".
I wouldn't apply this automatically to women's clubs. I believe the "L"
("Ladies") flex already takes into account the shorter shaft usual in
women's sets. However, if the female golfer in question is above an "L"
flex on the selection chart in the next section, you'd better take length
into account when selecting the shaft flex.
If the shaft you bought uses tip trimming to determine flex, you have a
finer-grain way of compensating for non-standard length. See the next
section for ways to achieve a between-grade flex.
Children's clubs - I confess to not knowing anything from direct experience
- 22 -
about clubs for pre-teens. I have some practical suggestions for clubs for
teenagers, based on having seen my own kids through from 12 to adulthood
on a variety of clubs.
Once kids are big enough to be at least within the range of women's clubs
(say, over 5 feet tall), they grow amazingly quickly and keeping them in
properly fitted clubs can be expensive. The way I dealt with it was to be
on the lookout for used clubs at garage sale prices. You can't buy these
just when you want them, so "stockpile" them. They do show up often enough
that you can always have the raw materials for the next set around when
they're needed. I don't think I ever spent over $20 for the a set of clubs
for my younger son (before work and regripping). I had to pay more for my
older son's clubs because, as a true left-hander, he required a rarer
commodity.
Here's what I did to make them a new set:
- Get a set not too much bigger than they'll need. Unless the kids are
at least the size of the average man, get a women's set. The reason is
the L flex shaft that will seem much stiffer after it's cut to the
proper length.
- Cut it to a length that will allow for a little extra growth, maybe
1/2". This will affect swingweight a little, but the most important
thing is that they may have to grip down ("choke up", in baseball
terms) a little. The kids should have fairly frequent lessons anyway,
but one purpose is to remind them where to grip the club this season.
- Regrip with a grip that feels comfortable to them. Size matters here,
since maintaining a good grip is so essential to a good game. A
proper-sized grip will prevent their perfecting bad habits.
No need to go for an expensive grip, or one that will last. Size and
reasonable comfort are all that will matter.
Several vendors sell sets of heads for younger children. I'm particularly
impressed with the junior set from Hireko, a cavity-back set 10% lighter
than adult components and, according to the catalog, intended for ages
5-10. But I admit to no expertise in this area.
- 23 -
4. SHAFT FLEX
Dave Tutelman
Copyright (C) 1993 - All rights reserved
One of the most important design decisions about the club is the flex of the
shaft. For that reason, this article is devoted just to shaft flex. Other
properties of shafts (and other aspects of the club) are covered elsewhere.
4.1 The Standard Flex Grades
There are five major grades of flex. From the most flexible to the stiffest,
they are: L, A, R, S, and X. Qualitatively, what these grades mean are:
L Ladies For women or high handicap
A Flexible For seniors or high handicap
R Regular For the average player
S Stiff For low handicap
X Extra-stiff For scratch player
This table is constructed from words in the Golfsmith and GolfWorks catalogs.
But they should really refer to swing speed and strength, not gender, age, or
skill. The point of extra flex is to get a little shaft action to increase
the clubhead speed at the moment it strikes the ball. (Remember, clubhead
speed is the single biggest determinant of distance.) If you are a slow
swinger, a flexy shaft will store up more energy and release it at the moment
of impact; a slow swinger with a stiff shaft won't get any extra "kick" at
all from the shaft. Conversely, a fast swinger with a flexible shaft will
meet the ball with the shaft still cocked (and the clubface likely open), and
wind up hitting a weak slice.
How do you judge which flex you need? Well, the reference catalogs (Golfsmith
and GolfWorks) have a number of tables that suggest measurement to determine
it. Here are some sample tables:
Criterion X S R A L
150-yard club (1) 8-9 6-7 5-6 4 3 or more
5-Iron carry in the air (2) >175 146-175 116-145 90-115 <90
Driver carry in the air (2) >245 211-245 171-210 135-170 <135
(1) Golfsmith catalog. (2) GolfWorks catalog
I think this is easier to see graphically, so I've reproduced (or, in one
case, estimated from another parameter) tables from the reference catalogs as
graphs.
- 24 -
Shaft Flex vs. Clubhead Speed
GolfWorks LLLaaaaaaaaaaaaaaaRRRRRRRRRRRRRRRsssssssssssssssXXXXXXXXXXXXX
|
Clubhead 5....:....6....:....7....:....8....:....9....:....1....:....1
Speed MPH 0 0 0 0 0 0 1
| 0 0
Golfsmith LLLLLLLLLLLLLLLLLLLLLLLLLaaaaaaaaaaRRRRRRRRRRssssssssssXXXXXX
Shaft Flex vs. 5-Iron Carry Distance
GolfWorks LLLLLaaaaaaaaaaaaaRRRRRRRRRRRRRRRsssssssssssssssXXXXXXX
|
5-Iron 8....:....1....:....1....:....1....:....1....:....1....
Carry Yds 0 0 2 4 6 8
| 0 0 0 0 0
Golfsmith* LLLLLLLLLLLLLLLLLLLaaaaaaaRRRRRRRRRRRssssssssssXXXXXXXX
* Golfsmith numbers estimated from recommendations for 150-yard club.
Note that GolfWorks tends to recommend a somewhat stiffer shaft than does
Golfsmith, for the same golfer characteristics. I can think of a couple of
possible reasons:
- Ralph Maltby of GolfWorks and Carl Paul of Golfsmith are experienced and
opinionated on all facets of club design and construction. That doesn't
mean they always reach the same conclusion. In this case they don't.
- Following in this vein, perhaps the experts disagree on whether to shade
their ratings in favor of distance or accuracy. A stiffer shaft will
probably give a straighter shot than a flexible one when it's not hit
quite right.
- In my experience, the average graphite shaft is softer (less stiff) than
a steel shaft of the same nominal grade of flex. Perhaps GolfWorks made
the table from experience with graphite shafts and Golfsmith with metal
shafts.
Before I give this a rest, let me point out that the Golfsmith book "Golf
Clubs - Design and Repair" includes the passages:
"Studies into golf club design and playability show . . . that
under almost all circumstances, golfers will perform better with
lighter swingweights and stiffer shafts."
and:
"Contrary to popular opinion, studies show that rather than
'jumping' into the ball, the softer more flexible shafts tend to
lag, leaving the clubface out of alignment with the hands and
therefore promoting misdirected hits. Stiffer shafts, on the other
hand, tend to better maintain the relationship between clubface and
hands through impact, and therefore provide straighter shots."
The "lighter swingweights" advice from Golfsmith should not be surprising by
now, but the "stiffer shafts" seems to contradict the fact that their charts
recommend LESS stiff shafts than GolfWorks. However, I think GolfWorks takes
shaft stiffness to the extreme, possibly pandering to the macho who wants to
- 25 -
say, "I need a stiff shaft 'cause I hit it so hard." I've seen other articles
by knowledgeable pros who say most people use TOO stiff a shaft.
Let me cite my own experience. On the GolfWorks chart, I'm a definite "S". On
the Golfsmith chart, I'm between an "R" and an "S". From a fair amount of
experimentation, I consistently hit better with an "R" than an "S". So I know
which chart I believe.
You pays your money and takes your choice.
4.2 Other Flex Grades
Some manufacturers (notable True Temper) may offer some of their shafts in a
finer gradation than the five basic ones. Under this system, the middle of
the basic grade is designated "300". Thus an "S" shaft is probably an "S300";
a somewhat stiffer "S" might be an "S400". As a rule of thumb, the "100"
subgrade is comparable to the next more flexible grade, and the "500"
subgrade is comparable to the next stiffer grade.
In my opinion, the subgrades are a waste of time unless you restrict yourself
to one model of shaft from one manufacturer. The reason is that there are no
industry standards for flex grades; each manufacturer decides what "S" means
for their shafts. If we're lucky, it may mean something similar from brand to
brand. But I've seen cases where there's even variation between models from a
single manufacturer. Given this uncertainty about the major grades, I'm not
sure what a subgrade would tell me.
Some manufacturers are going to frequency measurements to determine flex. In
fact, some articles in the Golfsmith Clubmaker magazine in the last half of
1992 suggest that all manufacturers are headed in this direction. However,
Brunswick is even giving numerical frequency grades to their shafts, instead
of the usual LARSX letter grades. In the Brunswick system, a shaft
oscillation of 550 cycles per minute is called a 5.5 flex, and corresponds
roughly to other manufacturers' "R" flex.
The Brunswick "Precision" model shafts are available only in the stiffer
flexes (grades 5.5 to 7.5). Because the flex grades are derived by frequency
matching, Brunswick claims that a set of shafts is matched better than the
competition within a matched set of shafts. I don't know if this is true, or
if it means anything in practice, but they do charge for the matching. The
shafts go for about $10 apiece, comparable to the most expensive steel shafts
available. In the other shafts, you're paying for light weight; in the
Brunswick Precision, you're paying for flex matching.
4.3 Other Flex Determinants
I have noticed a couple of other things that determine the effective flex of
a shaft.
Material: I (and others) have "observed" that graphite shafts seem to be
whippier than steel shafts of the same nominal flex. I put quotes around
"observed" because I haven't actually measured this on a deflection board for
a variety of shafts from a variety of manufacturers; it is just an informal
impression. It may be true, or it may be an illusion stemming from the better
- 26 -
damping qualities of graphite, or it may just be the collective imaginations
of the people with whom I've discussion it.
Anyway, I'd estimate the subjective difference between graphite and steel at
less than one full grade of flex.
Length: As the shaft gets longer, the effective flex increases. This is
well-known, well-observed, and stems from well-understood principles of
structural design. What it means to you is: if you're designing a club with a
longer-than-average shaft, choose a somewhat stiffer nominal flex than you
want for the final club, and vice versa. I'd say that a full grade
corresponds to about two inches of length.
Trimming Method: When you buy a shaft, you'll almost certainly have to trim
it at one end or the other to get the club length you want. If the shaft is a
taper-tip (rare for today's clubheads), you can only trim from the butt end;
the tip must be left alone if it is to fit properly into the hosel.
However, most clubheads these days take a parallel tip (also called a
"unitized" tip) shaft. This style of shaft has a constant diameter for quite
a few inches from the tip (typically more than six inches). This provides the
clubmaker an opportunity to control the flex by varying how much of the shaft
is trimmed from the tip and how much from the butt.
The tip is the weakest (flexiest) part of the shaft; the section at the butt
is much wider, therefore much stiffer. Thus, when you shorten the shaft, the
resulting section will be much stiffer if you trim away the tip and leave the
butt, and vice versa. In fact, that is the reason for the tip pre-trimming
instructions packed with most parallel tip shafts; it is to keep the flex
center of the finished shaft in roughly the same place as the center of the
raw shaft, as nearly as possible across all shafts in the set. The effect is
most pronounced in those shafts that come in a "combi" flex; e.g.- the True
Temper Lite shaft comes in an "R/S" combination flex. The pre-trimming
instructions call for trimming two extra inches from the tip to produce an
"S" flex.
You can use this effect to make a between-grade shaft flex. For instance,
with the TT-Lite shaft mentioned above, do the tip-trimming halfway between
the "R" and the "S" instructions and you'll have a between-flex shaft.
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5. CUSTOMIZING THE CLUBS
Dave Tutelman
Copyright (C) 1993 - All rights reserved
Here's where the rubber meets the road (or the driver meets the ball, so to
speak). It was hard to decide how to organize this section, because
customizing is really the mapping between two domains:
- The characteristics of the golfer for whom the clubs are built, and
- The characteristics of the clubs.
Should the chapter be broken down by properties of clubs, or of the golfers
that will use them? I finally decided that since I was trying to represent a
two-dimensional (at least) mapping, I'd need a two-dimensional organization.
So we begin with a table, where the columns are parts of the club and the
rows are traits of the golfer. If there is a customizing effect worth talking
about at the intersection, it is noted; for instance:
- For the trait "Hand Height"
- And the club part "Shaft",
- The "Length" of the shaft is entered.
After the table, the rest of the section is organized so that you can find
the effects noted in the table.
5.1 Effects of clubhead features.
5.2 Effects of shaft features.
5.3 Effects of grip features.
So scan the table, check out the traits of the golfer for whom you're
building the clubs, and go to the club features to read how to choose
components to match the clubs to the golfer.
One important caveat about using this table:
Don't try to cure FAULTS through choice of equipment. That should be handled
with lessons and practice. Rather, match the club to the characteristics of
the player's game and frame. Examples:
- DON'T try to cure a slice with a small grip, unless you're sure the grip
was too big to begin with.
- DON'T get a closed-face driver to cure a slice.
- DO match the flex of the shaft to the speed of the golfer's swing.
- DO choose the length based on the golfer's hand height and swing plane.
- It's OK to make the club more "forgiving" for a beginner, or for someone
who doesn't play enough to maintain a really consistent hit.
In short, build the club for the game to which the player can reasonably
aspire in the short term... say, before it's time to buy the next set.
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The Golfer Clubhead Shaft Grip
Clubhead speed (power) Loft Flex Diameter
[ see note 1 ] Torque Material
Hand height Length
[ see note 1 ]
Hand size Diameter
Trajectory (low/high) Loft Bend point
COG
Direction (slice/hook) Face angle Flex Diameter
Torque
Swing plane (upright/flat) Lie angle Length
Swing arc (sweep/downward) Sole camber Material
Sole bounce
Swing precision (repeatable?) Weighting Torque
[ see note 2 ] Sole camber
Sole width
Offset
Special problems:
- Back pain Flex
Bend point
- Hand, arm pain Material Diameter
Material
- Childrens' clubs
[ see note 3 ]
Note 1 - See also the section on swingweight, which is a composite of all the
parts of the club.
Note 2 - This refers to a beginner's club or a "game improvement" club, vs
the club of someone with a perfectly grooved swing.
Note 3 - Kids' clubs carry a bunch of challenges better dealt with as a
whole. It's covered in the section on club length, since that's the
most obvious problem, and most of the other considerations are
related to it.
- 29 -
5.1 Effects of Clubhead Features
Center of Gravity ( COG ) - The center of gravity can vary in three different
dimensions:
- Heel-to-toe: There are some that feel that increased toe weight helps
pull the clubhead through the ball and prevents slices. I'm not
convinced yet. However, the Ping Zing seems to indicate that Karsten
is convinced. Same for Golfsmith's Square Toe models, Acer's
"flow-weighted design", and several heads from ProSwing. So either it
works, or people are buying based on the proposition that it works.
- Face-to-back: Probably not a useful design parameter.
- Height: Aha! This matters...
A low COG tends to give a high trajectory (flight line) to the ball, and
vice versa. So:
- If you tend to have trouble getting the ball airborne, go for a low
COG.
- If you want to keep your shot lower out of the wind (a la Paul
Azinger), go for a high COG.
- If you want your drive to carry in the air, go for a low COG.
- If you want your drive to roll a long way, go for a high COG.
Many peripheral-weighted (cavity-back) clubheads have a big sole flange,
that keeps the COG low and gets the ball airborne.
Most short-hosel or no-hosel clubheads are designed for a low COG. For
instance, compare the Acer M160J with the M360J. Same loft angle (10
degrees), but the short-hosel 160 gives a high flight, while the high-COG
360 gives a flat trajectory and lots of roll.
Face Angle - It is possible to get woods with an open face angle or a closed
one. For instance, some closed-face woods are advertised as "curing" a
slice. I don't think it's a good idea to deal with a slice by getting a
hook-tendency club. Much better to find out what's causing the slice
(it's probably doing other bad things to your game as well) and cure the
disease rather than the symptom.
Go for a square face angle if you can.
Lie Angle - If your swing plane is more upright or flat than normal, you'll
probably want a lie angle to match. That's a simplistic view. In order to
design and build a club with a non-standard lie angle:
- Check section 3 on Club Length; there is a strong interaction with
lie angle.
- If you intend to achieve the angle by bending the head, check the
item on clubhead materials in this section.
Loft Angle - The larger the loft angle, the higher the flight of the ball.
Also, generally, the shorter the shot. Unless you have reason for going
non-standard, choose a set with standard lofts (e.g.- 5-iron loft of 28
degrees).
Beginners may want a little more loft, to get the ball airborne. But
remember that this problem may go away soon after you begin the game,
especially if you're reasonably well-coordinated or athletic; do you
really want to go club shopping again soon?
- 30 -
Heavy hitters with strong hand action may want a "strong" loft (a lower
loft angle), to get more distance and keep the ball lower and out of the
wind.
If you want to change the loft angle by bending the head, check the item
on clubhead materials in this section.
Material and Manufacturing Process - There has been a lot of controversy
about forged vs cast heads, or stainless steel (the usual cast clubhead)
vs chromed carbon steel (the usual forged clubhead). On the basis of the
puublished results of some controlled tests, I believe that material has
very little to do with it. The difference is mostly in the DESIGN of the
head. That is, usually
Forged = Carbon steel = "Muscleback" blade
Cast = Stainless steel = Cavity back
The few studies that mixed up these relationships came away concluding
that the difference in "feel" was really the difference between a cavity
back (big sweet spot) and a muscle back (small, critical sweet spot).
But there IS a practical difference in materials when you try to bend the
head to adjust the loft or lie:
- Carbon steel and 18-8 stainless take a bend well.
- 431 stainless can bend up to perhaps 2 degrees before being damaged.
- 17-4 stainless can't be bent without damaging it. Don't even try.
The reason for this is the hardness of the material. The less sure you
are of your loft/lie, the higher on this list you want to be. By the same
token, harder clubheads will not nick as easily and will probably last
longer; if you ARE sure of your loft/lie, move toward the bottom of this
list for a club that will look better longer.
Sole Bounce and Camber - The "bounce" of the sole is the angle the sole makes
with the ground when the club is held at a normal address. The term comes
mostly from sand wedges, which have a substantial positive angle on their
flange that keeps them from digging into the sand and burying.
The "camber" of the sole is the curvature. There are two different
kinds: heel-toe camber (illustrated in the section on Club Length) and
face-back camber. A clubhead that has a lot of both kinds is frequently
advertised as having "four-way camber".
A head with a negative bounce will tend to dig into the ground when it
strikes it. A zero or slightly positive bounce will skim along the
ground.
- If your swing uses a downward strike of the ball, a negative bounce
means you'll take a "beaver pelt" divot with relatively little
effort.
- If your swing is a sweep that contacts the ball at the bottom of the
arc, a flat bounce may save a slightly fat hit from becoming "play
the divot, it went further than the ball". A little face-back camber
added to such a clubhead will reduce the slowing of the clubhead from
friction with the ground.
Note that both swing styles are valid, and are taught by some following
of pros. The touring pros tend to take big divots with their irons and
sweep their fairway woods. Jack Nicklaus' tape and book "Golf My Way"
tends to encourage a sweeping swing with most clubs (even though that
- 31 -
point isn't made explicit).
Now let's talk about heel-toe camber. I believe it's very important, and
greatly prefer more of it. Quoting from Golfsmith's "Golf Clubs - Design
and Repair":
"The soles of all clubs, both woods and irons, should have some
contour from heel to toe, so that when the sole touches the
groun the contact point will be directly under the sweet spot.
This contour is particularly important in the irons where
divots are normally taken. With a flat soled club, the
slightest error in the lie angle would cause either the toe or
the heel to dig in at impact while the contoured sole has a
built in margin of error. Also, the contoured sole takes a
narrower divot, which permits the club to cut through the
ground with less effort."
I agree with what they say about the irons. However, I also find it makes
a surprisingly large difference in woods, even the driver. My most common
mis-hit with a driver is scuffing the ground before I hit the ball. Most
drivers have a fairly flat sole plate, so a corner (usually the heel)
catches the ground and turns the club; when I scuff a drive with a
conventional-sole driver, I usually hit a bad hook.
Last year, I experimented with two new drivers:
- Golfsmith's Big Gun has accentuated heel-toe camber. Most of the
times that I scuffed it, I got a high draw instead of a duck hook; I
lost a little distance, but usually got away with a respectable
drive.
- Acer's M160J has a keel sole, the reductio ad absurdum of camber.
When I scuffed the ground with that keel, it always dragged in the
center of the clubhead, without turning the club. You couldn't tell
from the flight of the ball that I had scuffed.
I practice what I preach with irons, too. I use a sweeping swing that
hits the ball without much divot. My irons are Golfsmith Tour Model IV,
with zero bounce (or perhaps even slightly positive) and as accentuated a
4-way camber as I've seen.
Sole Width - A narrower sole has less friction with the ground. However, if
you hit it fat, a narrower sole won't provide as much saving "skim" on
the surface; it'll tend to dig. In other words, if you are quite
repeatable with your swing and almost never hit it fat, you'll probably
want a narrow sole. A wider sole is a feature of game-improvement
clubheads for the less-precise golfer.
Weighting - Different designs of clubhead advertise their advantages
differently:
- "Bigger sweet spot is more forgiving." (Perimeter-weighted clubs,
frequently referred to as cavity-back.)
- "Puts the weight directly behind the ball for more distance." (Blade
or "muscle-back" clubs.)
Believe it or not, they're both telling the truth (as we hinted earlier
in the section on Physics).
If you always hit it on the sweet spot, you'll probably get more "feel"
(and possibly more distance) from a muscle-back blade. If you're less
- 32 -
precise then your concern is minimizing the damage from your off-center
hits, and a cavity-back is called for.
There are a variety of patterns for distributing the weight in a
peripheral weighted club, but they probably don't have all that much to
do with which popular model the club looks like. The important variations
to look for are:
- A big bottom flange: low COG helps get the ball airborne and makes
the sweet spot taller.
- A reduced bottom flange (concave like the Ping Eye 2, or even cutaway
like the Ping Zing): maximum heel-toe weighting to widen the sweet
spot.
- High square toe (new Golfsmith designs) or extra metal at the top of
the toe (Ping Zing): supposed to help the clubhead "swing through"
the ball and avoid a slice. I don't have any intuition for why this
works, but I've seen it in enough disparate places to give it some
measure of credence.
- Semicircular "ridge" around the edge of the cavity (the 845, and a
host of imitators with three-digit numerical model numbers): I'm
really not sure what if anything this does, except to make it look
like the current "hot model".
- Relatively small cavity: sometimes an indication of a cheap club
(both price and quality). Have they had so much trouble with the
strength of their heads that they kept the basic structure and
performance of a blade but put in enough cavity to look
"fashionable"? I wouldn't get one unless I knew enough about it to
know this wasn't the case.
5.2 Effects of Shaft Features
Bend Point - Also called "flex point", this refers to the height on the shaft
where the maximum flex occurs. In general:
- A low bend point gives a high trajectory of flight.
- A high bend point gives a low trajectory of flight.
Sounds simple enough.
If you have trouble getting the ball off the deck, get a low bend point.
If you hit it over the moon, get a high bend point.
If you're in between, get a mid bend point.
Many low-handicap players like a high bend point because it keeps them
out of the wind, giving them more distance. Of course, their strong
swings mean they have no problem getting the ball airborne.
True Temper makes a shaft, the Flex Flow, that has a different bend point
for each length (and it comes in 1/2" increments). Thus you can have a
low bend point for your 2-iron (hard to get long irons up) and a high
bend point for your 9-iron. I own a set of irons with Flex Flows; they
work decently enough, but I wasn't impressed with the quality control in
the manufacture. Also, the shaft has a very visible "pinch" at the bend
point; it just looks funny. I'd probably get something else if I were to
do it again.
Flex - There's a whole separate section on this; check it out!
Length - There's a whole separate section on this; check it out!
- 33 -
Material - A lot of people say they want a graphite shaft. Others say they
wouldn't touch a graphite shaft. Is either of them right? Is there
anything intrinsically wonderful (or terrible) about graphite?
I can think of only a couple of things about graphite vs. steel that
aren't covered elsewhere. (Flex, torque, and weight are covered
elsewhere.)
- Graphite has better vibration-damping than steel. I know of more than
one golfer with arthritis in his hands or arms, who insists on
graphite shafts because it causes less pain when he hits the ball.
The high-frequency vibrations don't get from the head to the grip;
just the low frequencies, which cause a dull thud.
When people say that graphite gives them more "feel", they're really
saying they prefer the low frequency thud to the full range of
vibrations from the clubhead.
- Graphite requires some special preparation of the clubhead. The top
of the hosel must be "coned" -- reamed out at a "soft" angle -- so
that the sharp edge doesn't cut the fibers and weaken the shaft right
at the top of the hosel. Many heads are made pre-coned today. But if
you're using a graphite shaft, either be sure your hosel is already
coned or get a 20-degree tapered reamer hard enough to cut stainless
steel.
I've also seen a recommendation that a ferrule be used on graphite
shafts, but the recommendation is hardly universal and makes no sense
to me. I say, use one if and only if the hosel is built for a
ferrule.
- This may be just subjective (I haven't seen recent data), but I feel
that steel shafts take abuse better than graphite. Certainly this is
true of abrasion; fur-lined bags are recommended for graphite sets.
But I suspect it's also true for repeated stress from the clubhead
making hard contact with the ground. While I have no qualms about
graphite for a driver, I'm a little queasy about graphite for irons
for this reason. (By the way, if you DO break a graphite shaft, be
very careful not to handle it at the break. The fibers sticking out
are tiny, brittle, sharp, and make splinters that are impossible to
remove from your finger.)
While I'm on the subject of durability, I have also seen old steel
shafts break from contact with the ground. In every case I've
observed, the shaft has rusted from the inside. This certainly won't
happen with graphite, but the data isn't in on possible other
age-related failure modes.
I realize I've said nothing about materials other than steel and graphite
(I include boron fiber in what I've said about graphite). That's because
I have no direct experience with them. I have yet to try out this
winter's putter, made with an alloy shaft. And I have never used nor made
a club with a titanium shaft. (My impression of titanium, based only on
reading, is that it's much like steel except that it's a little lighter
and damps vibration better, it doesn't rust, and it costs what premium
graphite shafts cost -- $50.)
- 34 -
Torque - This is a little-understood property that can cost big bucks.
- What is it?
This was explained earlier in the section on Physics. Actually,
"torque" is a gross misnomer for this characteristic; it's really not
torque at all, but "torsion". It is the angle of twist you can
deflect the shaft when you put a standard amount of torque on it.
(Torque is twisting force; the deflection it produces is called
torsion.) Anyway, the smaller this number the lower the deflection,
and the stiffer the shaft is against being twisted.
- What is its interaction with your game?
Ideally, the shaft would have zero torsion, but we don't want to hit
the ball with a telephone pole; we accept some torsion as the price
of light weight. Let's see the kind of problems a twisting shaft can
produce.
- As with flex, your hands start the club down and the clubhead
lags; if the timing is right for the stiffness, the clubhead
catches up just as you strike the ball. The actual effect of
torsion "lagging" is an open clubface; if it doesn't catch up in
time, you'll probably slice.
- If you strike the ground before the ball, the ground may impart a
twisting force to the clubhead that tries to open or close the
face at impact. Two ways to counteract this are low torsion
(don't let the shaft twist) and sole camber (minimize the
twisting force to begin with).
- Well then, why don't I just buy the shaft with the lowest torsion?
Go ahead, make Aldila's day. Torsionally stiff shafts cost plenty, in
dollars or weight or both. Consider the following (typical and
approximate) data:
Standard steel 2.0 degrees 125 grams $4
Lightweight steel 2.5 degrees 105 grams $10
Inexpensive graphite 4.5 degrees 85 grams $20
Low-torsion graphite 2.0 degrees 90 grams $50
Conclusion: if money is no object, get low-torsion graphite. If not,
here's my personal strategy:
- For the driver (and optionally the fairway woods), get graphite
in the torsional stiffness your swing needs. I've never seen a
table for this, but it seems to be related to flex. That is, the
greater your clubhead speed the more torsional stiffness you need
to make the clubface close by the time you strike the ball.
(Grafalloy's new Nitro shaft seems to deny this assertion,
offering a torsionally stiff shaft with whip. The returns aren't
in yet on whether this is worth the $50.)
- For the irons, you don't get as much swingweight advantage from
saving shaft weight. Unless you need graphite to make your
swingweight or damp vibration, try to do it with steel.
For the record, I have seen assertions that torsion has the same
beneficial effect as flex for a slower swinger; it allows the
clubhead to "kick" into the ball. Also for the record:
- 35 -
- I seriously doubt there's anything like the kick one gets from
flex.
- Whatever kick there is definitely isn't worth the badly aimed
head (and consequent off-line shot) resulting from a less than
perfectly timed swing.
In short, high torsion is a detriment to everything but your wallet.
Weight - As with torsion, you pay for low weight. The table above is roughly
indicative, except for the last line. The low-price house brand shafts
(the Golfsmith Carbon Stick or the GolfWorks DistanceMaster) are $18, 86
grams, and 4.5 degrees. As you spend more, you generally put the bucks
into low torsion or low weight, down to torsions below 2 degrees or
weights in the low 70s. It's really easy to pass $50 if you want to
stretch the weight or torsion specs.
For instance, Grafalloy makes a shaft (the VHM90) that specs out at 70
grams and 1.9 degrees; if you need such extreme specs, it'll cost you
$75.
At the other end of the spectrum, other component vendors that have
shafts comparable to the DistanceMaster and Carbon Stick for similar
prices ($13 to $23). Aldila's entry in this price class, the Low Torque,
goes for a different point in the specmanship, trading high torsion (5
degrees) for lightness (only 75 grams). So why do they call it "Low
Torque"? Beats me.
My strategy here is the same as with torsion; for the majority of your
clubs, you should be able to make do with a steel shaft of some sort, and
the most expensive steel costs less than the least expensive graphite. Of
course, you can't get a steel shaft that weighs less than 100 grams, but
that should be enough for all but the most exotic requirements for your
irons. (For a driver, especially an over-length one, do what you need to
do.)
5.3 Effects of Grip Features
Diameter - It's worth mentioning here the rule of thumb for determining
whether a grip is the right size for you. (The description appears, with
pictures, in the GolfWorks catalog.)
Take your normal grip, then remove your right hand (assuming a righty
golfer). Now look at the left hand, which is still gripping the club. If
the fingertips of your two middle fingers just touch your palm, the grip
is the right size. If they dig into the palm it's too small, and if they
miss by more than 1/8" it's too big.
So why (besides the above rule itself) would you opt for a larger or
smaller grip?
- A larger grip inhibits the "release" of the hands through the ball; a
smaller grip facilitates this release. For this reason, a too-large
grip might cause a slice, and a too-small grip a hook. But have a pro
look at your swing before you decide this is the problem; it may be
something else, and trying to fix it with the grip could make matters
worse.
- 36 -
- Since the large grip inhibits release, it may be inhibiting your
power as well as the ability to bring the clubface square to the
ball.
- Since the large grip inhibits release, it may be just the thing to
calm down your putting stroke if it's too "handsy".
- The large grip may be easier to hold for someone with arthritic
hands.
Material - Once upon a time, everyone used wrapped leather grips. When the
modern slip-on grip (a composite of rubber and cork) was introduced, it
quickly took over all but the very-low-handicap market. But the pros and
their imitators stayed with leather for a while because it seemed to give
a more intimate (i.e.- less resilient) contact with the shaft.
Today, even the pro-line clubs seem to be gripped with slip-ons. While
wrap-on leather grips still exist, they are expensive and harder to
install. I don't know whether the pros still use them, but few others do.
There are many grip patterns to choose from (pick what looks and feels
good to you), but really only one material choice left: do you want cord
embedded in your composite grip? The pluses and minuses of the cord grip:
+ Holds with less slip, especially with wet or sweaty hands (in case
you play a lot in hot humidity or rain).
+ Lasts longer.
- But your gloves (or hands) will wear out sooner; the improved
gripping power comes from increased friction, which means faster
abrasion of the surface it plays against.
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