Golf club (equipment)
Golf is played with golf clubs of various types. There are four major categories of clubs, known as woods, hybrids, irons, and putters. Wedges resemble irons and may also be counted among these. A golfer is allowed to carry up to fourteen clubs during a round.
While it is possible to play a range of different shots using only one club, modifying only the speed and direction of swing, this is not a particularly successful technique. It is much easier to keep the swing as constant as possible and achieve different lengths and characteristics of ball flight using a different club for each shot. To facilitate the choice of a club for any particular situation, all irons (and many woods and wedges) come in sets of similar clubs graded by loft (see below), shaft length, and weight. Clubs are numbered for identification with the smallest numbers indicating the lower lofts (a 5 iron has less loft than a 6 iron).
Various clubs are designed with the face having differing loft (the angle between a vertical plane and the clubface when the club is at rest). Loft makes a golf ball leave the ground on an ascending trajectory, not an upward direction of swing: with the exception of the tee shot, the club actually hits the ball in a slightly downward motion. The impact of the clubface compresses the ball. Grooves on the clubface impart a counterclockwise (from a parallel view of the swing) spin, known as backspin, on the ball, that when combined with the rebounding effect of the ball, give it lift. Typically, the greater the loft, the higher and shorter the resulting ball trajectory.
A typical set of clubs generally consisted of 2 woods, 2 wedges, a putter, and 9 irons, numbered 1-9. This has changed greatly in the last 25 years, as most players have opted to take 2, or even as many as 5, of the difficult-to-hit longer irons out of the bag in favor of higher lofted woods, known as fairway woods, and extra "utility" wedges.
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Types
- Woods are long clubs for long shots, with a shaft length about 40-46 inches or 100-115 cm, although some woods such as Black Rock's Killer Bee have been made with shaft lengths of up to 50 inches. Woods are used for the longest shots, ranging from 200 to 300 yards (180-275 m). The typical loft for wood faces ranges from 9 to 26 degrees. The 1 wood is usually referred to as a driver. They have large heads that are somewhat spherical in shape with a slightly bulging clubface and a flattened bottom that slides over the ground without digging in during the stroke. Originally the "wood" heads were made of persimmon or maple wood, but modern club heads are usually made of hollow steel or titanium. The first steel metal woods were filled with foam in order to ensure structural stability. The shaft enters the head at the top corner nearest the player through a hollow tube known as a hosel in such a way that the face of the wood is roughly at a right angle to one side of the shaft. Some companies, such as Callaway Golf, famously eschewed the hosel in order to place more useable weight in the head. This process resulted in far less of the shaft being affixed to a surrounding structure. This had the effect of weakening the bond between the shaft and clubhead while also exposing more of the shaft to direct contact with the ball on particularly poor swings and was often a culprit in shaft breakage in the more fragile graphite shafts.
- Irons are used for shorter shots than woods, especially including shots approaching the greens. Irons typically range from 36 to 40 inches (90-100 cm) in length. Iron heads are typically solid with a flat clubface. The typical lofts for irons range from 16 to 45 degrees. "Long" and intermediate irons (i.e. those with a lower loft) are usually played from fairway or other easy ground. These irons are typically a 1 iron up to a 5 iron. "Short" irons (with a higher loft) are played from difficult ground and especially for approach shots to the green. These irons are 5 irons to the very short and high loft 9 iron.
- Wedges are irons usually with a loft of more than 45 degrees. Pitching wedges are rather similar to other irons, Sand wedges have specially designed undersides, which utilize a feature known as "bounce", that make them suitable for shots from bunkers or from the rough. Gap wedges represent a compromise between a pitching wedge and sand wedge--hence their name. Lob Wedges have a very high loft and are used for approach shots, from sand, or difficult recovery shots requiring an extraordinarily high shot traveling a short distance.
- Putters come in a variety of head shapes and have a very low loft and often a short shaft. They are used to play the ball on the green, but may occasionally be useful for playing from bunkers or for some approach shots on courses with tightly mown fringe and fairways.
Construction
The parts of a club are the shaft, the grip, and the head.
The shaft is a tapered tube made of metal (usually steel), or graphite fiber. Some "matrix" shafts have incorporated two construction materials, such as a graphite shaft with a steel tip in True Temper's Bi-Matrix. The shaft is roughly 1/2 inch in diameter (12 mm) near the grip and between 35 to 45 inches (89-115 cm) in length.
Shafts are quantified in a number of different ways. The most common is the shaft flex. Simply, the shaft flex is the amount that the shaft will bend when placed under a load. The load in this case represents the swing of a given golfer. Golfers who have faster swing speeds generally use shafts that are less prone to bending, i.e. stiffer shafts. Another method of measuring shaft stiffness is the frequency of a given shaft, that is the number of cycles per second the shaft makes when struck by a tuning fork. The stiffer the shaft, the greater the frequency is. Different manufacturers have different standards for measuring the flex of a shaft, so one company's standard should not be taken as universal. For example, Grafalloy's Blue model tends to play stiffer than does Aldila's NV-65 shaft. Most shaft makers offer a variety of flexes. The most common are: L (Lady), A (Known as soft regular or Senior Flex), R (Regular Flex), S (Stiff Flex), and X (Tour Stiff, Extra Stiff or Strong Flex). Some companies also offer a stiff-regular flex.
It is widely known that most male golfers play shafts that are too stiff for their own good. A shaft that is too stiff will result in a loss of distance because the golfer is not strong enough to place enough load on the shaft to cause it to deform and thus "whip" through the ball. Occasionally, some golfers play with shaft flexes that are too light. The major problem caused by a "whippy shaft" is a loss of accuracy.
On off-center hits, the clubhead twists as a result of a torque. In recent years, many manufacturers have produced and marketed many low-torque shafts aimed at reducing the twisting of the clubhead at impact. The less the clubhead twists laterally, the greater the golfer's accuracy.
Prior to the 1930's, hickory was the dominant material for shaft manufacturing, but it proved difficult to master for most golfers, as well as quite frail. Steel was the ubiquitous choice for much of the next half century. Although heavier than hickory, it was much stronger, more durable, more uniform, and more consistent in its performance. Prior to steel, a player would need a slightly different swing for each shaft given the inherent inconsistencies in the hickory shafts. Graphite shafts first appeared in the 1960's, but did not gain widespread use until the early 1990's.
Widely overlooked as a part of the club, the shaft is considered by many to be the engine of the modern clubhead. Current graphite shafts weigh fractions of their steel counterparts which allows for an overall lighter club than can be swung at a much greater speed. Within the last ten years, performance shafts have been integrated into the club making process. These performance shafts all have various characteristics-some are designed to launch the ball high, others low, for example. They also allow for greater discretion for the modern golfer as every shaft model is slightly different. Whereas in the past one club could only come with one shaft, today's clubheads can be fit with dozens of different shafts, increasing the variety of combinations by an order of magnitude, creating the potential for a much greater fit for the average golfer.
The end of the shaft opposite the head is covered either with a rubber, synthetic leather (Winn Grips), or colloquially, a leather grip for the player to hold. The modern grip has also undergone a number of iterations and the vast variety of models makes it far easier for a discriminating golfer to find a model that is comfortable to him or her.
Each head has a face which contacts the ball during the stroke (but the head of a putter may have two faces).
Older persimmon and maple woods had heads that were primarily made of the aforementioned materials save for a possible metal sole and/or faceplate. These wooden headed clubs were dense and heavy and as a result remained miniscule in comparision to today's clubheads. Their smaller surface area also made consistent good contact more difficult.
Gary Adams, founder of Taylor Made Golf, is considered the father of the modern metal wood. Adams began to market his club in the late 1970's, but it was nearly a decade until metal woods established a firm foothold in the golf community. Many PGA Tour players still used persimmon woods into the 1990's.
Metal woods provided an advantage over persimmon in that they presented a stronger and lighter material which allowed manufacturers to make larger clubheads. Larger clubheads resulted in larger faces, which meant that it was easier to contact the ball, particularly in the desired area.
For a comparison of Titanium to Steel, please see the Regulations section below.
Traditionally, most iron heads were made by forging, which involves the careful shaping of the club head through hammering and pressing of heated steel. Today, most modern golf club heads of all types, not just irons, are cast through a process known as investment casting. This process allows manufacturers to redistribute the weight into the perimeter of the club, known as perimeter weighting, which helps to increase the accuracy of mishit shots. Forged clubs are still prized for feel and "workability", the ability to curve a ball's flight intentionally.
Regulations
The ruling authorities of golf, the Royal and Ancient Golf Club of St Andrews (R&A) and the United States Golf Association (USGA) reserve the right to define what shapes and physical characteristics of clubs are permissible in tournament play. Several recently developed woods have a marked "trampoline effect", a large deformation of the face upon impact followed by a quick restoration to original dimensions which acts as a slingshot, resulting in very high ball speeds and great lengths of tee shots. Current USGA and R&A regulations differ with respect to acceptable limits of the "trampoline effect". Therefore, a few club types may not be played in tournament or professional play under USGA jurisdiction, but are allowed elsewhere.
Furthermore, the use of titanium as a metal in golf club construction has revolutionized the equipment industry. Since titanium is both lighter and stronger than steel and has amazing corrosion resistance, it is an ideal metal for golf club construction. Manufacturers could now make woods with greater volume, which increased the hitting area, and thinner faces, which reduced the weight. The first mass-produced titanium wood bought in large quantities, The Callaway Golf Great Big Bertha, was introduced in 1995. It was an, at the time, massive 253 cubic centimeters of volume. Subsequent drivers were even larger, which made the effective hitting area much larger. Thus the driver went from the most difficult club to hit well, to one of the easiest. The USGA has curbed the volumetric growth of drivers by instituting a size rule which states that no club can measure greater than 460 cubic centimeters.
Other large scale USGA rulings involve a 1990 suit, and subsequent settlement, against Karsten Manufacturing, makers of the PING Brand, for their use of square, or U-grooves in their immensely popular Ping Eye2 iron models. The USGA argued that players who used the Eye2 had an unfair advantage in imparting spin on the ball, which helps to stop the ball on the putting greens. Ping ultimately changed the design of subsequent Eye2s, the older clubs were "grandfathered in" and allowed to remain in play as part of the settlement. Today square grooves are considered perfectly legal under the Rules of Golf.