Wood (golf)

A modern 460cc driver alongside an early 1980s persimmon driver.

A wood (also called a driver) is a type of club used in the sport of golf. Woods are used to hit the ball farther (greater distances) than any other type of golf club.

Woods are so called because, traditionally, they had a club head that was made from hardwood, generally persimmon^[1] but modern clubs have heads made from metal, for example titanium, or composite materials, such as carbon fiber. Some golf enthusiasts refer to these as "metals" or "metal woods" but this change in terminology is not strictly necessary, because while the material has changed, the style and intended use has not. The change to stronger materials has allowed the design of the modern woods to incorporate significantly larger heads than in the past. Because of the increase in club head size, in 2004 the USGA created a new stipulation for the size of the club head. The legal maximum (by the rules of golf) of a wood is 460 cubic centimeters^[2].

Woods are numbered in ascending order with the driver, or 1-wood, which is designed to hit the ball the greatest distance, having the longest length and lowest loft, typically between 7 and 13 degrees. However there is no industry standard and some overlap occurs. With the typical loft of a 2-wood being 12-13° a 1-wood and 2-wood could have the same loft. Other differences in club design, such as head size, face roll, weight distribution, lie angle, or club length, could also differentiate a 12° 1-wood intended for tee shots and a 12° 2-wood intended for fairway shots. Most club manufacturers’ matched sets include 1-3-5 numbered woods. Even numbers are less common with modern clubs. The number of the club is mainly a reference for the player to easily identify the clubs. Other identifiers have been utilized such as strong and plus to differentiate various lofts within a line of clubs.

Woods generally fall into two classes, drivers and fairway woods, with a traditional set of 14 clubs comprising a driver, two fairway woods (3 and 5), ten irons and a putter^[2]. Many modern sets tend to include hybrid clubs, which combine some of the characteristics of a wood and an iron, to replace the 5 wood and longer (3 and 4) irons.

Drivers

The longest and lowest-lofted wood is the driver, or 1 wood, and has the longest range of any club in a golfer's bag. It is designed to be hit off the tee for the first shot of long-yardage holes. The driver can also be hit from the turf, although modern deep-faced drivers require a high level of skill and a certain amount of luck regarding the "lie" of the ball to execute such a shot correctly. Some 2-woods also have a similar deep-face oversized design, used for tee shots requiring less distance than the player's average drive or for players with slower swing speeds to achieve the optimum distance using their slower swing tempo. The driver is generally the largest, longest, and often the lightest of the golf clubs in the player's bag. With the increased design technology in modern clubs, the cost of drivers has dramatically increased and now cost about $100 up to $2199 .

Fairway woods

A Strong 2 Wood

Higher-number woods are generally known as fairway woods and, as their name suggests, are designed for shots from off the turf of the fairway that still require long distance, such as the second shot of a par-5 or a long par-4 hole. They have two important features: a higher loft to lift the ball out of the turf and over low obstacles like hills, and a shallower face height which allows a player to hit a ball from the ground using the exact center of the club, providing greater distance for such shots. These two design features enable players to hit fairway woods off the ground with ease. Fairway woods are also useful off the tee depending on the hole; players may for instance wish to play their tee shot short (known as "laying up") due to a dogleg or a hazard in range of their driver, and will opt instead for their 3-wood. This club is made with a slightly shorter and stiffer shaft and more loft than a driver or 2-wood, and is used through the green for long high shots.

Usage

The most common set of clubs has three woods: 1-, 3- and 5- woods. However, there are many variations depending on the player and the course, and fairway woods of any number from 2 to 15 are produced and preferred by various players. The 7- and 9-wood are common among ladies, male seniors and children.

Design

The head of a wood is roughly spherical in shape with a slightly bulging clubface and a generally flattened sole that slides over the ground without digging in during the swing. Traditional "wood" clubheads were made of wood; beech wood or ash prior to the twentieth century, and later persimmon or maple. Modern club heads are usually hollow steel, titanium or composite materials, and are sometimes called "metalwoods" or more recently "fairway metals". Pinseeker Golf Corp. innovated the first stainless steel metalwood called the Bombshell in 1976. The design was somewhat untraditional and did not have the promotional success needed for profitable long term marketing - it was discontinued 3 years later. In 1979 Taylor Made produced a traditionally shaped stainless steel wood head called "Pittsburgh Persimmon" which achieved market acceptance by the mid-1980s. Oversized heads made from aluminum appeared in the mid 1980's but were slow to catch on since their introduction was via independent component manufacturers and not the larger endorsement based club manufacturers. Very large size drivers (300-500cc) arrived with titanium metallurgy which meant reasonable 'headweights' could be achieved with very large thin shelled but strong structures. By the mid 2000's, titanium heads could be made to 1000 cc (Golfsmith Inc made 1000 cc in the mid 2000's). Around this time the USGA decided to limit the size of driver heads to around 460 cc since the rule requiring heads to be of a traditional shape was being unduly stretched. However, during this period the clubmaking business needed some financial help so a number of new untraditional, but USGA qualifying, head shapes appeared - torpedo and square/rectangular to attract the buying public to potentially game improving designs particularly regarding better mishit outcomes.

The typical loft for woods ranges from 7.5 to 31 degrees. Driver lofts generally center around 10.5 degrees but the desired loft is very dependent upon the player's swingspeed (low swing speeds need higher lofts), while the average 3-wood has a 13-16 degree loft and the average 5-wood has an 18-19 degree loft. Higher lofts than that overlap with irons, but many players prefer high-number woods to low-number irons wherever they can be used as, with the same loft, the fairway wood's launch angle is higher and the distance is greater. The loft of any given club number varies between manufacturers and classifications; higher-lofted drivers (as high as 16 degrees) as well as higher-number fairway woods are often preferred by ladies and senior players or other slow swing speed practitioners, as they get the ball up in the air more easily at lower clubhead speeds.

The shaft length in woods varies from about 40-48 inches (100–115 cm), with the current standard length for the driver being 45 inches, formerly 43.5 inches. Graphite shafts are usually preferred for woods due to their light weight, which enables users to generate higher clubhead speeds and thus greater distance. The maximum legal length of a shaft by USGA and R&A rules is 48 inches^[2], though some woods used in long drive contests have been made with shaft lengths up to 50 inches long.

Construction

A rare solid carbon fiber driver, circa early 1990s

Shaft

The shaft is the true engine of the wood. Widely overlooked, the proper shaft increases distance and accuracy, while a poor shaft can lead to inconsistent shots, slices, and reduced distance.

The oldest shafts for all golf clubs were made of Hickory wood. The shaft was whippy and light, but inconsistent in flex from club to club and quite fragile. Beginning in the 1920s, steel shafts started making an appearance, though the USGA and R&A did not allow their use in sanctioned tournaments until 1929^[1]. These shafts traded the lightness and flex of the wood shaft for vastly increased durability and consistency, and were the only type of shaft in general use on any club until the early 1990s. The modern "graphite" shaft (technically a carbon-fiber composite material) currently in use today is the best of both worlds; it is lighter and more flexible than either steel or Hickory, while having similar durability as steel, at the cost of slightly reduced shot consistency due to increased torque (though this has vastly improved on recent generations of shafts). Graphite shafts gained widespread popularity in the mid-1990s; although the carbon-fiber composite technology had been available since the early 1970s, it was very expensive to produce and nearly impossible to mass-market^[1]. Advances in producing, forming and curing composite materials have made carbon fiber much cheaper, and now virtually all new woods, regardless of price, have graphite shafts.

Shaft flex has a very pronounced effect on the power and accuracy of a wood. Every wood is somewhere in between the two extremes of flex, from the extra whippy, to the extra stiff. Whippy shafts are used by those who have low swing speeds and stiff by those who have faster swing speeds. The flex of a shaft allows it to store energy from a player's downswing, and release it as the head makes contact for increased club speed at impact. A shaft that is too stiff cannot be flexed by the golfer during their downswing, which reduces club speed at impact. A shaft that is too whippy will retain some of its stored flex at contact, wasting energy.

Shaft torque is also a concern. Flex and torque are generally related; the more a club can flex, the more it can also twist around its axis (though this is not always the case). A shaft that can torque easily is less forgiving of off-center shots as it will allow the head to twist, causing pulls and pushes. Low-torque shafts resist twisting for more forgiving behavior, but tend to be stiffer and require more power for proper distance. The latest generation of driver shafts combine a flexible shaft with a stiff tip, giving the golfer the required flex to "whip" into the ball while reducing clubhead twisting.

Head

Wooden heads predominated until the late 1980s. They had evolved to include a metal sole and a metal or plastic faceplate. These wooden headed clubs were dense and heavy, and were generally much smaller than today's clubheads. Their smaller surface area also made consistent contact more difficult, as the sweet spot of these clubs was considerably smaller than today's models.

Gary Adams, founder of TaylorMade Golf, is considered the father of the modern metal wood. Adams began to market his club in the late 1970s, but it was nearly a decade until metal woods became more popular with most golfers. Callaway Golf is also largely responsible for the current design of metal woods; the original Big Bertha driver introduced players to the "oversize" driver with a larger and deeper clubhead (at the time it was 190cc in volume), giving maximum club face and a deeper center of gravity. Callaway Golf continued to expand the size of the clubhead to increase these effects, resulting in the Bigger Bertha, the Great Big Bertha, and others in the line. The current incarnation of the Big Bertha driver is 460cc. As a result of the rapidly-increasing size of driver heads in the late 1990s, the USGA curbed the volumetric growth of drivers by instituting a size rule which states that no clubhead can measure greater than 460 cubic centimeters^[2], though larger clubheads exist for long-drive contests and informal games.

Today, many metal wood clubfaces (and most driver clubfaces) are constructed out of titanium. Titanium has a higher strength to weight ratio than steel and has better corrosion resistance, so it is an ideal metal for golf club construction. Manufacturers can also make clubheads with greater volume, which increases the hitting area, and thinner faces, which reduces the weight.

Hosel

Traditional woods had a very thick hosel, often wrapped with thin cord, which provided a very secure joint between shaft and head at the cost of a higher center of gravity. Modern metalwoods have largely done away with the hosel altogether, instead anchoring the shaft within the clubhead. This allows as much mass as possible to be contained in the clubhead, lowering the center of gravity.

References

1. ^ ^{a b c} http://www.golfeurope.com/almanac/history
2. ^ ^{a b c d} http://www.usga.org