GOLF CLUB MANUFACTURE
Any golf club has three basic parts:
* The golf grip - the part you hold
* The golf shaft - the part that connects the golf grip to the golf head
* The golf head - the part that actually hits the golf ball
If you walk down the golf club aisle of a large sporting goods store, you'll see a variety of
designs for all three of these parts, but you'll also notice that all golf clubs have certain
similarities. That's because every golf club used in a round of golf that's either part of a
tournament or that might count toward a golfer's handicap must conform to rules established by
one of two organizations. In the United States, the rules of golf, including golf club regulations,
are established by the United States Golf Association (US GA). The rules of golf for the rest of
the world are established by The Royal and Ancient Golf Club of Saint Andrews (in Scotland).
For the most part, the rules established by the two bodies are the same, though there are some
differences. Now let's look at the main parts of the club.
The Golf Grip
The grip of the golf club is important because it connects the golf club to the golfer's hands.
According to the rules of golf, recognized by both ruling bodies, the grip has to be round,
without obvious bumps, lumps or hollows. You'll see grips made of rubber or leather with an
assortment of small holes, grooves or ridges. All of these qualities are designed to make it
easier for the golfer to hold onto the golf club without making the grip so large that it will run
afoul of the rules. There are various sizes of grips to accommodate different hand sizes and grip
styles. According to most experts, the ideal material and design of the golf grip are a matter of
The Golf Shaft
The shaft of the golf club connects the grip to the head and, like the grip, must be basically
round in cross section. Most modern golf club shafts are made of either steel or a carbon-fiber
and resin composite. Carbon fiber has the advantage of being lighter than steel , but golf
clubs with carbon-fiber shafts also tend to be more expensive. In addition, some golfers say that
hitting a golf ball with a carbon-fiber club feels different than hitting the golf ball with a steel-
shafted golf club. This difference arises because steel and carbon fiber transmit vibrations
differently. As in grips, golf shaft material tends to be a personal preference.
The stiffness of the golf shaft is another variable. Most manufacturers rate their shafts in one of
six degrees of stiffness.
From least to most stiff they are:
* L - Ladies
* A - Seniors
* R - Regular
* F - Firm
* X - Extra Firm
* S - Stiff
As you can see, there isn't a grade for "wobbly" or "limp." Most golfers, at least in the United
States, seem to prefer a golf shaft that is stiffer, and manufacturers have obliged. But if golfers
prefer stiffness to limpness, why not make everything super-stiff? The answer has to do with
distance and strength.
If you're Tiger Woods, or if you swing a golf club as he does, your body will coil and uncoil
during a golf swing so that you apply plenty of energy to the face of the golf club when it meets
the ball. If your swing is this good and if you are this strong, you want a very stiff golf shaft so
that every bit of energy you generate in your swing is delivered to the golf ball, and none is
absorbed in making the shaft of the club bend and vibrate.
If, on the other hand, you do not have a Tiger Woods swing, then you can get a golf shaft with
some flexibility to do some of the work of sheer muscle with a well-timed "whip" motion that
stores energy from the top of the swing in a bent golf shaft, then releases it in time to deliver
that energy to the golf ball. How much flex might you need for your particular swing? If you're
serious about answering this question, then you should have a golf pro (a club professional
who's a member of the P GA of America ) analyze your swing and make a recommendation.
The Golf Club Head
The head of the golf club is where all the energy of the swing is transferred to the golf ball.
There is more variation in the appearance of golf club heads than there is in either shafts or
grips, but all the variations fall into one of three broad categories: the heads of golf woods, golf
irons and golf putters.
Golf Woods have the largest heads of any golf club. These large clubs are designed to send the
golf ball 300 yards or more with a single swing. What is it about the bulbous shape of the golf
wood that suits it for these long-distance strikes? The answer has to do with the wood's golf
shaft, especially in the largest wood, called the driver. Wood shafts are considerably longer
than the shafts of most other golf clubs. This length increases the power that can be transferred
to the golf ball, but it also makes it less likely that the ball will meet the the quarter-sized
sweet spot in the middle of the golf club face. When an off-center hit occurs, the head of the
golf club tends to twist, pointing the face in an unintended direction, and sending the ball the
A golf club designer has to balance a number of factors. A heavy golf club head best resists
twisting and so suffers the least from a less-than-perfect swing. On the other hand, a golfer can
generally swing a club with a lighter head at a greater speed, which generates more energy to
be transferred to the golf ball and so sends the ball a greater distance. Over the past 100 or so
years, golf club designers have attempted to strike a balance between light and heavy clubs.
The large head of a golf driver and the combination of metals like steel, titanium and bronze
that go into various drivers, are attempts to balance stability and light weight. The driver head
shape allows designers to move the weight in the head to points that enhance stability (points
that are different for each brand of club, and provide one of the differences touted by
manufacturers when claiming superiority for their clubs). The driver head shape also allows the
head to glide over grass and ground rather than digging into the turf.
Golf Irons are designed for a greater variety of shots than golf woods. Where woods tend to be
optimal for long to very long shots, the shots made using golf irons range from 200 yards or
more, in the case of 2 irons, down to 40 yards or less in the case of the various golf wedges.
Golf Club designers must cope with the same issues in irons as in woods, but their shorter
shafts and the less exaggerated swings with which they are used have led to different solutions
for different types of players.
Only 25 years ago, most companies' golf irons were very similar -- a blade-shaped head with
most of the weight concentrated low and in the center of the club. This design gave an
additional emphasis to shots in which the golf ball was hit with the golf club's sweet spot. The
heads of these golf clubs were steel, and usually shaped by forging -- hammering hot metal
under great pressure. When a golfer hit the golf ball off-center, there was very little in the golf
club's design to prevent it from twisting and delivering a disappointing shot.
In the last 25 years, designers have developed golf clubs that have approximately the same
weight as the older golf clubs but have it distributed around the perimeter of the golf club, so
that the head is far more resistant to off-center twisting and therefore far more forgiving of golf
swings that are off line by a few millimeters. In addition, modern metal alloys have allowed for
larger iron heads, which increases the size of the "sweet spot," thereby increasing the possibility
of good results with a less-than-perfect swing.
If you look in the golf bag of a P GA Tour player, you'll probably see the same sort of forged
blade-style golf irons you would have seen 25 years ago. That's because their concentration of
weight behind the sweet spot make the most of a professional's very consistent, very accurate
swing. Recreational golfers, on the other hand, have embraced the perimeter-weighted iron for
the good results they get even with less consistent swings.
Golf Putters have a relatively simple job: to strike the golf ball with a face perpendicular to the
path of a gentle swing and cause the golf ball to roll along the ground until it falls into a hole.
Twisting is still a concern with off-center hits, but a golf putter is designed to transfer far less
energy to the golf ball than either irons or woods.
It's interesting, then, to note the incredible
array of shapes taken by the heads of putters -- blocks, blades, short, long, thick, thin, etc.,
and the various patterns of lines found on the faces. So why is there such variation in a golf club
designed for such a simple task? Because the mechanical simplicity of putting places most of the
pressure on the golfer's mental processes, where there is room for far more variation than in
any golf swing.
The Parts of the Club Head
The head of the golf club has several parts: the hosel, where the head connects to the shaft;
the face, which actually strikes the golf ball; the sole, which is the part closest to the ground;
and the back, which is on the side opposite the face. We've talked a bit about the design of the
back, and there's not much to say about the hosel, so let's look at the face and the sole.
When you hear an announcer for a golf tournament talking about the player's selection of a
club, you'll generally hear whether the player has chosen a wood or an iron, and then a number.
The number is related to the angle at which the face slopes back from vertical when the club is
held in its normal position facing the ball. A higher number for the golf club represents a greater
degree of slope away from vertical, generally resulting in a higher, shorter shot. There are
some slight variations between manufacturers, but the club numbers and their related slopes
generally look like this:
The slope is important for two reasons. First, the face will launch the golf ball on a path
perpendicular to the plane of the face at impact, so a more "laid back" face will start the ball on
a higher trajectory. This is crucial when a golfer tries to send the golf ball over some obstacle,
or when the golfer wants the golf ball to come back down at a steep angle, which tends to result
in a shorter roll after landing. The second important aspect of the slope is spin -- the greater
the slope, the greater the spin.
In the 450 millionths of a second that the golf ball and golf club are in contact, as shown in the
animation to above, the golf ball does several things. First, it deforms quite a bit, flattening
against the face of the golf club. As the ball begins to rebound to its normal globe shape, it
starts to slide up the club face. Finally, just before it leaves the club, the ball returns to its
familiar shape and begins to roll up the face. By the time the ball has left the club face, it is
spinning quite rapidly. According to the US GA, a golf ball hit by a wood or one of the longer
irons (3 to 5) will be spinning at approximately 3,600 RPM when it leaves the golf club. The
same golf ball struck by a pitching wedge will spin at nearly 6,000 RPM when it leaves the club.
A spinning golf ball is a good thing because the rapid spin provides aerodynamic lift, causing a
spinning golf ball to travel higher and farther than one with no spin at all.
The spinning ball is
also less influenced by small gusts of wind, making for a more predictable shot. One of the other
features you will notice on the face of a golf club, the grooves, also help provide spin.
The grooves on the face of a golf club serve two purposes. First, they provide just a bit of "bite"
for the golf ball as it's sliding up the face, helping it to spin more rapidly. Next, if grass is
trapped between the ball and club at impact, the water in the grass will be squeezed out by the
nearly 3,000 pounds of force generated by the average swing. Like the tread on an automobile
tire, the grooves on the club face give the water somewhere to go so that the golf ball doesn't
skid up the face without spinning.
Ideally, the sole of the golf club will minimize the twisting of a bad hit. In woods, the broad, flat
sole with rounded edges helps the head glide over the surface of the grass without digging in.
Shots using irons tend to take patches of the turf away (the patch is called a divot), so the sole
of irons are designed to slice through the turf evenly, without twisting or unexpected tugging to
disrupt the golfer's shot.