Sports Knowledge Base - Golf Clubs .

A golf club has three components

• the Head,
• the Shaft and
• the Grip.

The individual specifications of a golf club affect your ability to swing and ultimately the quality of your ball flight. There are five important features that affect performance:

• shaft flex
• weight
• length
• lie angle and
• grip size

The rules of golf constrain golf club designs, but the goal of clubmakers is to create golf clubs, within those rules of golf, that maximise the physics of the golfer's swing while allowing for a range of swing error to provide an accurate, long, yet forgiving shot. The better your swing, the less forgiving club you require.

A standard set of golf clubs consists of three woods (the 1-driver, 3, and 5), eight irons (3, 4, 5, 6, 7, 8, 9, and PW), and a putter - twelve clubs.
The rules of golf allow you to carry fourteen clubs in your bag, so many golfers add another iron or a speciality wood. After all, the more tools we have in our toolbox, the easier it is to do our job!

When you're just starting out in golf it's not necessary to have a full set of clubs-in fact, all you need is five clubs.
A putter, sand wedge, seven iron, seven wood and three wood will get you started and give you an idea of the different length and height each club is supposed to travel.

Most golfers have as their minimum arsenal one set of irons, multiple wedges, several drivers and a variety of putters. This is because your foursome all gets together at the tee where you use your driver. The pressure is high to perform well. Hopefully you end up in the fairway, spread out all over the golf course. As you work your way through the hole using your fairway woods and irons. Eventually, you all come back together again on the green.
So, where do you need the most weapons at your disposal? It is where the stakes are highest and the pressure to perform reaches its zenith. That is at the tee and the green. The adage "drive for show, putt for dough" does have meaning. That is why most golfers have multiple drivers and putters and one set of irons.

The advancement of golf clubs goes hand-in-hand with the advancement of golf balls. As ball designs began straying from harder wooden construction, golf clubs were no longer expected to have to withstand the impact of a hard wooden ball. This allowed golf clubs to be constructed from newer materials and with different designs.
Of all the materials different club makers and designers used, iron was found to be the best material for a golf club and is still widely used today. Of course, today there are graphite shafts and titanium clubs as well, but these are fairly recent developments, and mainly reserved for the more pricey drivers.

There is a huge assortment of clubs, each for a different purpose and to be used in a different situation. A common set of clubs may contain several drivers (with varying weights, head sizes, and lie angles), 2 through 9 irons, a pitching wedge, a sand wedge, and a putter.

• The drivers have a club head significantly heavier than that of any of the other clubs. These are generally used for the first shot of the hole and will hit the ball the furthest due to a larger transfer of energy from the more massive club head to the ball. The drivers also have a shallower lie angle (the angle between the club shaft and the club face) than most of the irons, but there is some flexibility in the angles amongst different drivers for different length fairways.
• The irons are ranked from 2 to 9 and the lie angle becomes greater with each. The lower irons are used to hit the ball further while still a ways from the green while the higher irons are used to hit the ball higher with a shorter horizontal displacement.
• The sand and pitching wedges are designed for chip shots where you are quite close to the green or simply need to get out of a deep sand trap. These clubs allow for a very vertical shot with minimal horizontal displacement.
• The putter has no lie angle and is simply designed to keep the ball on the ground as it travels across the green, hopefully ending up in the hole.

Different clubs have different shafts and different shaft lengths that also affect the flight of the ball, in addition to simply accommodating people of different heights.
When looking at the face of a golf club you will notice that there are grooves running horizontally across the club face. The purpose of these grooves is to grip the ball during the impact and impart a backspin on the ball that will help the ball gain loft and remain in the air for a longer period of time.
USGA rules regulate the size of grooves on the club face. They may be no deeper than 0.020 inch and no wider than 0.035 inch, and the flat area between grooves must be at least three times the groove width or 0.075 inch, whichever is smaller.
This is discussed in more detail in the club-ball interaction and aerodynamics sections.

Loft describes the vertical tilt of the club face. Face angle describes a horizontal tilt in woods.

• If the face 'faces' straight ahead; the face angle is zero, or square.
• If it faces left; it is 'closed (or 'hooked')
• If it faces away from the golfer; it is 'open'.

Total weight is important, but so is how the weight is distributed over the length of head and shaft. Swingweight describes this distribution. Two swingweight systems are in use, one using a fulcrum 12 inches from the butt of the shaft, and the other with the fulcrum at 14 inches.

More about weight

The face of a wood is curved in two directions, like the surface on the rim of a doughnut. The amount of curvature is described by two radiuses. Face bulge is measured in a horizontal plane and face roll in a vertical plane. Values are from 7 inches to 20 inches in steps of ½ inch; a typical value for a #1 wood is 9½ or 10 inches.

A physicist has done a mathematical analysis of the effect of this curve, and concludes that the curve tends to drive the ball in the opposite direction from the curvature due to the ball's spin, which comes from hitting it off-center. As a result, the ball is more likely to go straight. He also concluded that golfers who hit the ball hard benefit from a more deeply curved head.

With the improvement of technology, newer and better golf clubs are being released. However, not all of these clubs are endorsed by the USGA. Some of them, such as hollowed out titanium clubs, have a higher coefficient of restitution and impart a greater force on the golf ball.
For this reason the USGA has declared that clubs with a coefficient of restitution greater than 0.83 are not approved.