technology tutorial

To appreciate what we have today, we should first take a brief look at product evolution. A visit to the USGA headquarters in New Jersey is a real eye opener. There you will see virtually all of the old clubs of the past, as well as the steps taken in lost wax process investment casting, the steel shaft evolution and why little steps were put in, and so on, that led to today's products. It is a wonder that people such as Gene Sarazen could play persimmon heads with wooden shafts and do so well. The wooden shafts would change characteristics due to heat and moisture virtually every day. The heads would nick and need constant repair. And yet he was able to score a double eagle two at Augusta on the 15th hole.

If you look at the old tapes of Shell's Wonderful World of Golf, you will find Messrs. Snead and Hogan playing a 7,000 yard course in Houston, using old forged blade irons and persimmon headed steel shafted woods. And they did very well indeed, with Hogan putting for a birdie on virtually every hole. And all of these folks were using balls that were not very lively and cut readily. Further, we hear stories that individual handicaps have not come down that much since the days of Hogan and Snead, suggesting that product progress is more hype than reality. We must dispute that suggestion. The past performance of such legends of the game was due to their tremendous talent. And the handicap statistics now include many players who just don't have the time to play enough, have two wage earners in the family and cannot get to the course as often as they want. Further, we have many more seniors today, who have lost a little flexibility but want to continue on. Such factors tend to raise the average handicaps and do not give a more realistic indication of the real progress being made.

If you look at the Senior Tour you will find plenty of examples of men who are hitting the ball just as far, or even farther, than in their primes. Often, they do not have to manipulate the ball from left to right, or right to left, the way they once had to do. They simply fly over the obstacles with their normal shot shape.

You can also judge for yourself, if you can locate some woods and irons from the 60's or the 70's. Try hitting them at the practice range and immediately compare the results, club by club, to the models you have, or to the most recent models. You will find some or all of the following results:-

-In short, you should find that the newer designs are much more forgiving, easier to use, and do hit the ball farther as well.

- However, unless the new equipment is fittted to you and your swing, a good design is essentially worthless. There are tradeoffs that must be made as you select these new clubs, which are explained further in the subsequent points. Recently MSN had a Slate column, entitled, "Chuck Those Woods". We encourage you to read it, at http://slate.msn.com/id/2078176/ where the author describes his frustrations after spending $1,500 for a "custom" set of clubs. He does make some very valid points. What Pro's are playing is almost certainly irrelevant to you. Prices have become outlandishly high. Spending a lot of money does not ensure that you end up with something worthwhile. And oversized clubs can be a problem for some players.

- This fellow shoots in the 90's but has been fitted with long steel shafts. It sounds like one of these static measurement fittings, with hand to floor distance, and so on, was used as the fitting guide. If so, he was fitted badly, without dynamic considerations. The chances are that he should be playing graphite shafts and not steel shafts, for one of many things. If the clubs do not fit, he will continue to struggle irrespective of practice and lessons. The explanation of why very large heads can be a problem to many players is incomplete. As you will soon learn (see Point 16 below), inertial drag is the root cause. And it can be overcome with proper design and a little care in what you select. Since you have gotten this far in perusing this site, you are already on your way. Read through our Club Fitting section and the subsequent points here and you should be able to take advantage of the properties of the new designs. They work well provided they fit.

- For the habitual slicer, offset designs became practical. Here the hosel is curved backwards so the leading edge of the face has been moved back and does not protrude ahead of the hosel and shaft. This helps straightening out the ball flight.

B- The introduction of new materials for woods, especially drivers, seems to be very positive for many if not most players. Some of the most well known materials are, 6AL-4V Titanium; 465 maraging steel: 2 of the Beta Titaniums; and 15-5 stainless steel. Their properties are not identical, i.e., tensile strength, yield strength, density, elongation, and hardness, but each offer great possibilities for further design progress over 17-4 stainless steel. Since Ti-6-4 (meaning titanium 90%, aluminum 6% and vanadium 4%) is the most popular at the moment, for brevity we will concentrate on that.

-It is about 58% of the density of 17-4 stainless steel. This opens up all sorts of design avenues of improvement. Since Ti 6-4 cannot be heat treated after forming to increase its strength, more and more companies have turned to forging the material. This forging truly increases material strength which allows better energy transfer to the ball at collision. Since the density is much lower, heads can be made much larger for a given weight. We now see heads at 300 to 400 cc's commonly (even 500cc's recently)- not even dreamed of just a few years ago. (see question 7 of FAQ'sfor a discussion of playability).

- Stronger lofts can now be employed and tend to work well for strong players. - The center of percussion and the vibratory node can be seperated further, rather like what is found on aluminum baseball bats, so that the head has what is often called a larger "sweetspot". (see

question 7 of FAQ's for more details).

- Inserts of heavier materials can now be more readily attached at key spots on the head to change club characteristics , i.e., locating it at the rear of the sole to further heighten ball flight and lengthen ball carry.(see the Golf Tryst woods of the Product Catalog as an example).

- Springier faces, with a trampoline effect, can now be made. This is a controversial subject, with some designs ruled non-conforming by the USGA. There is a body of thought which argues against the design, saying that if you fail to hit the ball in the center of the face, you will direct the ball to the left or right depending on point of contact. Others argue that the spring action has to fit your swing too perfectly - otherwise the ball leaves the face either too early or too late and energy transfer is actually reduced. And yet, there are many examples of players who have found these clubs to be beneficial, who claim they have "hot" faces that propel the ball farther. The jury is still out on this subject, generally speaking, but we do know that there are players who are benefitting from these heads.

C- Graphite Shafts have had as much impact, especially for woods, if not more, as any other advance to date. These carbon fiber composites are made out of thin strings of fiber that are rolled into sheets. The sheets are then cut into patterns (a little like a tailor cutting patterns for parts of a garment), wrapped onto a mandrell and carefully wound about until there are sufficient wraps for the given design. The whole thing is baked, then sanded, painted and inspected. Techniques have improved greatly in the last 10 years and these are not the fragile pieces often seen in the past. The strings come in 3 general categories;- standard modulus; high modulus; and ultra high modulus. Each have somewhat different properties, but standard is a touch heavier than high, which is a touch heavier than ultra high. None are better than the other in an absolute sense. You employ them, sometimes in combination, depending on what you are trying to do, what sort of a club you are trying to make.

All of them are very much lighter than steel, in many cases more than 60 grams ( 2oz.) lighter. They can be made either stiffer or more flexible than steel shafts, but it is difficult to design the low torque values inherent in steel shafts without a loss in tip action. Tour pro's tend to use steel shafts in their irons for better control, where accuracy and not distance is their goal. However, more and more players overall have tended to use graphite shafts for just about everything with good satisfaction. The gains in ease of use has not been confined to seniors and ladies, but has been a big plus all across the spectrum of players. The features that come from using graphite shafts are commonly:-

- Lighter clubs overall with heavier heads, i.e. a 43" driver that may have had a 200 gram head with a steel shaft before can now be made with a head up to 212 grams with no increase in strain while swinging. More effective mass at impact means more distance.

- Clubs can be made longer than before, up to 50" in some drivers. The added length generally yields a gain of about 7 yards per each extra inch due to the longer arc and the higher impact velocity that the golfer can achieve. While it is true that most players have trouble with lengths beyond 45", (squaring up the face is difficult and they lose some accuracy as well), there are nontheless a certain few who handle very long clubs well.

- Designers can use lower lofts , say 10 degrees instead of 11 degrees on a driver, since the greater tip action found in a well designed shaft will produce a higher ball flight than before. At collision, the lower loft on a well struck shot produces better energy transfer to the ball. For long hitters this tends to get the spin of the ball, the rpm's in flight, down to more optimum levels.

- Flex points can be easily placed in the shafts at key locations for assorted players, i.e., low for the slower swings, towards the middle for the higher speeds, and higher yet for + 105 mph swingers. This tends to restore, to orient, the head to its natural loft at impact which the player started with at address.

D- Golf balls have improved so greatly in recent years that many feel that this is as big a breakthrough area as anything else that has transpired. They do not seem to cut or nick the way they once did, they go farther and straighter, and they do not go ovate or out of round as was common before. If you can, you should have your PGA pro recommend what fits your swing and your equipment. You may have to do some experimenting to match a ball to your club heads so the ball compresses optimally and springs off the face at your desired launch angle. The many choices are so numerous that we cannot list them here. In general, you will find:-

- Different compressions, such as 100, 90, ladies (or 80), as well as no compression given but rather a some generic description that describes the type of player who should use the particular model. In general, the long hitters would choose the 100 while 90 would serve most men and 80 would serve most women.

Note:- If you are shopping for balls, do not bounce several balls off the floor thinking that the one that bounces highest is the liveliest. You cannot compress it enough to find out anything meaningful. Indeed, a ball that is less lively could bounce higher.

- With either an open face or a square face club the player can rotate the club to open or closed at address to fade or draw the ball as he chooses. The sole will of course rotate too. To hook the ball, the face will decrease in loft and point slightly towards the ground while the sole lifts off the ground. If he chooses to fade he does not need to rotate the face open very much, so the leading edge will not lift off the ground enough to prevent contact with the ball.

- In the case of a closed face club you are stuck with a with a club that can only pull the ball to the left. If you try to open the face for a fade the leading edge lifts off the ground too much to allow easy contact with the ball. The sole digs into the ground and lifts the face. For this reason we do not recommend closed face clubs. In our experience you will be better served with square or slightly open faces.

Bounce is created by designing the trailing edge of the sole so that it is closer to the ground than the leading edge. It is almost exclusively used in irons and is critical for wedge play. In general wedges with less bounce are better for fairway shots, light ruff, and thin or wet sand conditions. Large amounts of bounce is useful for heavy sand (to prevent digging) and out of deep grass. ( see item 6-c of Club Fittingfor further discussion, and ideas on fitting).

There are many good iron sets using designs with no bounce, or with curved soles, or with a slight amount of bounce. We find that the negative bounce concept promotes digging into the earth. With typical fairways cut at 5/8 of an inch or higher, players find it difficult to use negative bounce clubs and make a crisp contact with the ball.

- If it is towards the rear it will propel the ball at a higher launch angle. This is because the club head and shaft are not absolutely rigid. Upon impact, the club head loses some velocity. Since the cm of the head is so far back the head curls upwards, rotating around the cm during the collision, imparting a higher launch angle.

Of course, as you contemplate a wood purchase, you will have no way of knowing where the cm of the head actually is. You should first determine the type of ball flight you want - high, middle, or low. (You already know what your difficulties are, if any).

- In the case of a wood made of stainless steel, it will tend to have its cm slightly forward, and the ball filght will be close to the rated loft. If you have trouble getting the ball airborne, for example, choose a loft that is around 11 degrees or even higher.

-In our experience, many people play fairway woods with too little loft. These clubs are there to advance the ball with accuracy, and land on a green without too much roll. Unless you have a problem of very high shots, you should try to find more forgiving lofts, like 15 or 16 degrees on a #3 wood and 20 or 21 degrees on a #5 wood.

- As for titanium drivers, they tend to have their cm back in the head, yielding higher ball flight. Here a 10 degree driver will produce the equivalent ball flight as a 10.5 degree to 11 degree stainless steel driver. You will have to check the description of the driver carefully to see what the manufacturer has to say about the head in question.

The time of contact between ball and driver club face is astonishingly short- between 4/10,000 and 5/10,000 of a second. We have a very hard striker hitting a very hard ball so this is not completely surprising. And the force from such a short impact is huge- well over a ton at 100mph swing speed. Most of the mass in the momentum equations (MV) is found in the club itself, with a small amount coming from the shaft and the player's arms. Estimates show that most men contribute around 80 grams more of effective mass than women, on average. This is not much and explains why there are many smaller people, men and women, who can propel the ball a long way. Most of the mass is given to you by the manufacturer, so there is not a lot you can add in the way of muscle. The time is too short. It becomes clear, therefore, that the keys to distance are:-

The drawing below was made from collision tests putting a load cell on the hosel of a driver and hooking it up to an oscilloscope. We used a tour player from the LPGA who brought her club up to 101 mph at impact. (this drawing is from one of our patents). The build up of force from the short impulse should be obvious.

-The left hand side of the curve shows the moment in time when the club and the ball first come into contact. As time passes the ball compresses to a maximum, at the peak of the curve. The right hand side off the curve slopes down to zero force which is the moment when the ball and the club completely separate. The word "impulse" is used to describe a rapid force of very short duration. That is what we have here. In physics we can express this as, net force x time interval = change in moment. Or Ft=p2-p1. If we divide both sides of the equation by t (time interval) we get, F=p2-p1/t. Now "t", the time interval, becomes a divisor. The smaller you make the time interval, the more force you apply to the ball, all other things be equal.

-If that lady Pro could have shortened the contact time between ball and head, while applying the same force, the more force she would have imparted to the ball. The peak of the curve above would be higher and the time in milliseconds would be less. The area under the curve would have been the same but the whole dynamic would be different. Shorter time contact means more force to the ball - more distance. For you, the player, this means you have to carefully select your "distance clubs" to make sure of the materials being used and the particular design of the head. In general, you want a head with high hardness and high stiffness.(see Item 16 below, Head Materials-Properties-Uses).

The standard way of measuring the shaft flex is to affix it to a deflection board. The butt end is securely fastened and the head end is suspended freely. A 6 lb. weight is then hung from the head, at the hosel, and the whole club will droop, with the tip deflecting the most. You then measure in inches how far the tip is from the horizontal line where you started and this figure tells you your relative stiffness. The longer you make a club in any given shaft rating, S, R or what have you, the more the club will deflect at the tip. The reverse is true if you make the club shorter, of course.

The industry does not have any agreed upon standard, for any of the lengths, but when you examine the shafts of the many manufacturers you find their actual shaft deflections are not too dissimilar. Here we tend to think of a 44" driver that deflects less than 5 inches as X-stiff; between 5 and 6 inches as Stiff; and between 6 and 7 inches as Regular.

There is another method of measuring relative stiffness and that is by loading the club into a frequency machine. When you pull down the head a bit and then release it, you cause it to vibrate. The vibration cycles are measured in cycles per second, cps, or cycles per minute, cpm, depending on what machine you care to use. The higher the number, the stiffer the shaft. The lower the number the more flexible the shaft. The shorter the club, the higher the number and vice versa for the longer the club. This is a very useful tool for custom fitting but the deflection board seems to have much greater use due to its simplicity.

This is the angle formed when the club sole is perfectly flat on the ground. It is deliberately put in at an angle that is set by the manufacturer. If the angle does not fit you there can be problems. This is of concern mainly with irons, where you want to take a divot by slicing through the earth. At impact, if the angle is too upright the heel will dig into the ground and the head will rotate, pulling the ball to the left. On too flat a lie the reverse will happen and the ball will fly to the right.

Players often adjust without even thinking about it. When the club is too flat they lean towards the ball and pull their hands in and down, trying to bring the toe up and the heel down. And the reverse happens when the lie is too upright. This can throw the swing out of kilter after a while. If your address posture is poor, then you may be causing the problem rather than the club.

As you swing the club, centrifugal force bends the shaft and head towards you, especially on long clubs and trivially on short clubs. So a fairway wood with a 56 deg. lie, for example, would become more upright by about 1 deg. Many shops would have the player address the ball with club in hand and see if they could slide a 25 cent piece under the toe snuggly. If it passed too easily the lie was too upright. If it woudn't pass at all, then the lie was too flat. This was done in recognition of shaft bending in actual play. The better way of checking is to put tape on the sole of the head and swing normally on a mat. If the tape is bruised in the center, it should fit nicely. If it is in the heel, the club is too upright. If it is at the toe, the club is too flat.

Practically speaking, if you are a slicer and have trouble hitting to the left, a slightly upright lie may not be a bad idea. If your natural play is a draw, then you may have to be more precise in your selection. On wedges the clubs are so short to begin with that most players do very well with the standard lies.

As you view a wood looking down at it, you will see that the face is curved from heel to toe, with a bulge at the middle. This curve is called horizontal face bulge. It is there to help the player if he fails to hit the ball in the center of the face, in line with the cm. It will tend to direct the ball to the right on toe hits and to the left on heel hits.

- In either case, a toe or a heel hit, there will be a loss of distance. Failure to hit the ball with the center of the club face, in line with the cm, simply reduces the effective mass of the club as it strikes the ball. It is the equivalent of a glancing blow.

The radius of the curve will depend on the center of mass, cm, location. If the cm is forward in the head, the curve will be small. If the cm is at the rear, the curve will be larger. If the cm is in the middle, the curve will be in between the two. (Woods are much wider than irons meaning the distance between the toe or heel from the center is much greater. This produces a much bigger twist on an off center hit and necessitates a compensating horizontal face bulge not needed on irons).

It is important that the player try to bring the head square to his target line. This is just as important as hitting the ball in the center of the face. Otherwise he can largely negate the aid found in the face bulge. For example, if he makes an outside to in swing path and cuts across his target line, he will impart a side ways glancing blow to the ball that could counter any beneficial spin from gear effect. The face will be open at impact, producing a slice spin of some magnitude. (see 13 below for more clarifcation).

The concept is to place the bulk of the weight of a given iron around the perimeter of the back to create stability, among other things, on off center hits. Although the idea is quite old, it has only been practical to make in the last 30 years or so. The principle is rather like that of a tight rope walker using a balancing pole on a high wire to counter any of his movements that might lead to a fall. It works in practice, just as it does on woods made of metal.

What is not generally known is the effect this concept has had on lofts. It is now easy to redistribute weight to the sole, thus lowering the center of mass, cm. This in turn increases the launch angle- you get higher shots. To restore a more normal launch angle, the loft is made stronger. As you have already observed from 3- above ( Loft & Lie Angles ) the lofts are much stronger today. Years back, a #9 iron was 45 deg. typically. Today 41 and 42 deg. #9 irons are common. The net result is the given iron also goes farther. ( Since metal woods are hollow, they have been designed similarly and they go farther for the same reason. ) Not many people buy or use #2 irons anymore because they feel the #3 iron does the job of a #2 and is easier to use as well.

There are skilled players who stick with the non cavity back designs because they prefer the "feel" and believe they can curve the ball to the left or the right more readily. However the preponderance of players seem to find the cavity back quite satisfactory. The benefits are:-

-The shaft is not completely rigid, and will twist during the downswing, and on an off center hit. Too much or too little can cause problems. Years back this was a big concern especially with graphite shafts. Good numbers were not yet established for the multitude of swing speeds and swing paths. Now the data has been gathered and the designs for various applications are pretty routine.

-The manufacturers call the twist factor "torque" and so rate their shafts in degrees of torque, such as 2.5, 3.0, 3.5, etc. all the way up to 7 degrees. The value is measured on a simple machine. The back end has a solid clamp where the butt of the shaft is firmly attached and cannot rotate. The tip is put into a second clamp that is horizontally in line . The second clamp can rotate as a unit and is firmly attached to the tip so it will rotate with it. A small weight is attached to the side of the second tip clamp and allowed to drop. The amount of turn is then measured in degrees and becomes the shaft's rating. Steel shafts tend to have less torque than graphite shafts, although very low values can be made in graphite as well. The complication in graphite is that as you take out the twist you may also make the tip a little too rigid for a good whip like release at impact. Fortunately most applications and most players do not require very low torque values and can employ graphite shafts in virtually all their clubs.

The sketch below illustrates, among many other things, how the shaft will twist when arriving at impact. Note that it can rotate either way before collision. If the shaft fits the player's swing, it will be rotating to a square position, trying to close, just at impact. If it does not fit, or the player makes a poor pass at the ball, it is unlikely that square contact will be made. It will twist either way on impact, as described in 10 above.

The low position for the slower swingers give them some tip action needed to help accelerate the head and get the ball airborne. For the fast swingers, a low flex point would sling the head around, out of control. Consequently they need a high location.

- It is also bending in, by centrifugal force, towards the player. This puts the actual lie at impact slightly more upright than the rated lie of the club. The difference may be as much as 1 deg. on a long club, although it will be insignificant on a short club.

- If the shaft is too flexible, the player will generally hit a high fade or slice. Here the shaft will also be lagging, the face also open, but the tip will be soft enough to turn the face upward, producing the high shot.

-Fig.2 above is a well executed swing with the shaft and head releasing strongly and squarely, closing towards a hook position. This position is difficult to reach with shafts that do not match the player reasonably well.

- Up to now, we have been looking at various conditions while assuming the club head was in a square position at impact. To complete the picture, it is necessary to explore what happens with the club head in other positions, as well as the influence of swing path on the results. The swing path the player uses will greatly influence the actual flight of the ball. Figures 1 and 3 below show two extreme paths, with the club head in a poor position, just at the moment of impact:-

- Fig. 1 shows an inside to out path with a very closed face at impact. Most likely he is flipping his wrists, either trying to square the club, or is seeking more distance. This results in a smothered or duck hook, whether you strike the ball at the toe, or the center. At the heel, it might never get airborne. Were we to change the path to the outside to in of fig. 3 and keep that closed face, we would be looking at a pull to the left of some sort, depending on the point of contact on the face. It would also be a bad shot.

- Fig. 3 depicts the classic slicer's swing, with everything open at impact. The side spin would largely negate any of the benefits of face bulge and gear effect, no matter where contact was made. On a heel hit, a weak high fly is expected. On a center hit the player should find a classic slice with the ball drifting to the right without too much distance. At the toe it could be anything including a ground ball.

- Fig.2 is a square face and square swing path that should result in a good, on target, shot. If the player hits the ball at the toe or heel with this otherwise good position, gear effect will enter and keep the shot manageable. No one can always hit the ball in the center of the face, in line with the cm. This shows the importance of getting the club to a square position as much as possible. From this position you have a good chance of a reasonable result.

- In Fig.4 we see a perfect draw swing. The target line shown above is down the middle of the fairway, for ease of drawing. In actual play, the golfer could well be aiming down the right side of the fairway, intending that the ball start that way and drift left. The point is that the face is square to his target line, whatever that may be, at impact. A small amount of side spin has been applied to the ball, because the face is crossing the ball slightly as it continues to go inside to out.

- In fig.5, we have the reverse- a perfect power fade swing. The head is square at impact and imparting a slight side spin that produces the fade. Please note that, all conditions being equal, a power fade goes just as far as a power draw, contrary to popular belief. Fades are not as long when the player executes poorly, and imparts too much side spin.

-Swingweight is an attempt to measure the distribution of weight throughout a club. It will show if the weight is towards the head, in the middle, or towards the grip. It has been theorized that if a set of clubs is made so each one has the same swing weight, then the "feel" of each will be the same as any other. The picture below shows the scale on which swingweights are determined:-

- The scale is rather like a see-saw, but the pivot is not in the center, but is located only 14 " from the grip end. Since the club is much longer than 14 ", as you place it on the scale, the head will droop towards the floor. The little balance device is then slid back and forth until the club is in balance and horizontal. On the side of the scale are swingweight numbers. The point where balance is made is the swingweight number, i.e. c-8, or d-2, etc. This scale of numbers is called the Lorythmic scale.

-Some have felt that lower figures would serve women best, while increasing numbers would apply to increasing swing speeds. Typically, c- 6 to c-9 was recommended for ladies; c-9 to d-1 for seniors; d-0 to d-2 for most men; and higher than d-2 for the stiff shaft players.

- The concept does not actually exist in engineering. If we were to put a 6 lb. weight on the butt end and a 3 lb. weight on the tip end, the swingweight would not change. However, nobody could swing the club. Golf swings are curvelinear and not straight line motion. The resistance therefore is not mass but moment of inertia. This essentially means you must be more precise about how much mass you are dealing with and how far away it is from the axis of the swing, in this case your wrists. This is an engineering problem that the user must hope the designers have properly calculated since he will not be able to verify values on his own. ( see

item 13 of FAQ's for an in depth look at moment of inertia ).

- In balance, some people swear by swingweight and cite all sorts of cases of success with the typical swingweights listed above. There is no doubt that too much head weight makes a club difficult to swing. We can say that the scale does tell us if the weight is pitched in one direction or another, and to that extent it is useful.

-Offset is a design aid to combat the player's tendency to arrive at impact with the face of the club open. The hosel is set leading the club face. This problem is most severe on long irons and woods, due to their length. The sketch below shows a typical design for an iron (on the left) and a wood (on the right):-

-Today, irons are made around 1/2 to 1 inch longer than before. Consequently offset is being found in every club of the set, i.e., #3 and #4, 4 to 6 mm's, #5 and #6, 3 to 5 mm's, and the balance including the wedges between zero and 3.5 mm's.

- In practice, the little extra gap between the hosel and the face gives the higher handicapper a much better chance of squaring the club face at impact. There are many low handicappers who are also using moderate offsets on their irons with great success too. It is most helpful on their #2 and # 3 irons due to the increased lengths prevalent today.

- For those players with a slice problem, who cannot seem to defeat it in spite of lessons, offset on their woods may be a great aid. This would be especially noticeable on the driver, it being the longest club in the bag.

- The following tabulates the most popular materials used in head construction, with their most important properties and their area of use. These are listed in order of hardness, with the softest at the top and the hardest material at the end of the list.

Material	Hardness	Tensile Strength	End Use
aluminum	B50-60	70	woods, putters
carbon steel	B60-70	70	irons, putters
431 stainless	C18-25	120	irons, putters
6-4 titanium	C32-36	145	woods, inserts
17-4 stainless	C34-38	140	woods, irons
15-5 stainless	C36-44	150	woods
10-2-3 titanium	C42-45	205	woods
465 maraging steel	C45-55	265	woods

- Both hardness and stiffness are crucial to head design. Even the very slow swinger is applying a ton of force during the impact with the ball. The head must distort, creating losses. Losses mean less energy transfer to the ball- less distance. Even if you select a good material for the application, if it is not backed by a good design then the losses will be higher than they should be.

- If you ignore design for a moment and just concentrate on the properties above, you should notice something that may be a little surprising. Look at 17-4 and 15-5 stainless steel. Their properties are very good - they are high on the list. The best is 465 maraging steel! In other words, these materials are very good for golf clubs. If you only look at these properties it makes you wonder why the titanium alloys are so popular. (Pure titanium is just C24-28 in hardness and is seldom used).The answer is in material density.

- 17-4 stainless steel is 7.8 grams per cubic centimeter, 7.8g/cc. 15-5 stainless is slightly denser at 7.81g/cc. And 465 maraging steel is a little less dense at 7.75 g/cc. The most popular titanium alloy, Ti 6-4, is just 4.5 g/cc. In other words, Ti 6-4 is only 57.6 % as dense as stainless steel. With these Ti alloys you can now build much larger heads without the danger of face and wall collapse. The trend to large heads has been fueled by heavy marketing and has definitely caught on with much of the public. Whether or not they are right for you is another question. You are unique, just as your fingerprints are unique. Other players including the Pro's are simply not you. What they play doesn't matter. You have to settle on what fits you.

1- In a well designed head it is now easier to separate the center of percussion ( the point where the head does not twist on impact ) from the vibratory node ( the point where vibrations at impact are lowest ). This larger distance between the two points can be considered an enlarged sweetspot. Good designers can do almost the same enlargement on stainless, but it is quite difficult to accomplish in practice.

2- Every head has a center of mass (cm ). When you hit off center the head will twist. The more off center the worse the twist. This is a glancing blow, in essence. You not only lose energy transfer (reduce effective mass) to the ball but some accuracy as well. A wider face will lessen that twist a bit, alleviating some of the mass and accuracy loss. In technical terms, a wider face has a higher moment of inertia due to the fact that the length back to the head's cm, from either the toe or the heel, is longer.

3- In these large heads, the face is proportionately less of the total mass of the head. Therefore the distance from the face to the cm of the head is longer. This means the cm of the head is more towards the back and that helps get the ball on a higher trajectory. To achieve a given launch angle of the ball, the designer can now make the face with a little less loft, a degree or so depending on the design. The more you get towards the perpendicular in loft, the more energy transfer you impart to the ball. It is not a lot, but you will take all you can get.

4- There is what may be a psychological factor too. Some people feel more confident using a large head. They feel surer about making reasonable contact. In many cases this confidence feeds on itself and the player does better.

1- The cm is further away from the hosel and shaft. This makes it more difficult for the player to square up the head during the downswing, due to inertial drag. Here the larger moment of inertia now given to the whole club by employing a wide head actually works against you. You can end up making more glancing blows than before and negate all of the above features that are possible with large heads. You will want to check the design you are looking at to see if the manufacturer addresses that problem, with a narrower face, with weighting in critcal areas, etc.

3- Thinned sections are necessarily less stiff. Unless the heads are properly designed, they will distort more on impact than otherwise. In that case big is definitely worse. The faster you swing the worse the losses.

4- On badly off center hits on very wide faced drivers, at the toe or the heel, you are putting a lever action back at the shaft, right above the hosel. The wider the face, the longer the lever. Shearing the shaft is a real possibility.

- It is not possible to say for certain what will be best for you. If you are a high handicapper you may want to be a little conservative and concentrate on the heads below 400 cc's, say 350 or even 300cc's. The same might apply if you fight a slice. In point of fact, you would not select by volume but by face height and face width. You would try to keep face width down, say, between 93 to 97 mm's. And a face height of 44 to 48 mm's should produce a good mid flight launch angle. (The lower you go in face height, the higher the ball flight. The higher you go in face height, the lower the ball flight).

- For the player who wants to stick with steel heads, as you can see from the properties above, this is good material. There is much good golf being played every day with them. And they are easier on the family budget too, if that is a concern.

- No matter what you select, you will have to find a ball that matches both your swing and your equipment. You want a ball to optimally compress and spring off the club head at a launch angle that you want - high , middle or low. Unless you have a teaching pro at hand familiar with your needs and equipment, it is likely that you will have to find the proper ball by old fashioned trial and error.