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Technical FAQ Answers 1. What does the term "COLD ROLLED BETA I" refer to that is on Wishon Model 915CFE drivers? Metals can be formed into their required shape for processing in several ways and at a variety of different temperatures. It is always easier to form a metal when it is hot than cold because heating 'loosens' the molecular bonds of the metal, thus allowing less force to shape the metal. However, heating the metal to a point that 'loosens' the molecular bonds also can decrease the strength and elasticity of the metal. By forming the metal in a cold state, the original grain structure is retained and with it, the strength and can be kept at higher levels. Cold forming is also more expensive because forming the metal cold requires more force, so typically a larger press or larger piece of forming machinery has to be used. return to top 2. What does the CFE designation mean on the Wishon 915 woodheads? CFE stands for Computer Face Engineered. In the case of the Wishon 915 woodheads, not only is the precise face thickness of EACH woodhead in the set modeled on computer, but each driver and fairway woodhead face is machined to its precise variable thickness design on a CNC (Computer Numeric Control) Machining center. So in short, our computer modeling dictates the design thickness of each face for maximum performance, and then a computer controlled milling machine actually creates the face that was computer modeled. return to top 3. Why are the faces of the Wishon 915 woodheads designed and manufactured with three different metals? That is true – the face of each Driver model is machined from Cold Rolled 10-2-3 Beta Titanium, the #3 wood face is machined from cold rolled 6/4 Titanium, and the faces of the #5 and 7 fairways are each machined from forged Carpenter 455 high strength steel. The reasons? 1) The larger the face, or more precisely stated, the TALLER the face, the more chance for spring effect and with it, maximizing the COR (Coefficient of Restitution – a numerical indication of energy conservation of an object) and the resulting ball velocity off the face. And the less the loft on the clubface, the more face deflection is possible and with it, also maximizing the COR and the resulting ball velocity off the face. That adds up to saying the driver will always have the best chance for maximizing the COR and ball velocity, and therefore becomes the best model for using the metal with the highest strength to elasticity ratio, the 10-2-3 Beta Titanium alloy. 2) It is just not wise from a design standpoint to make a #3, 5, 7 woodhead with a face height much taller than 38-40mm, because of the golfer's perspective/confidence in getting the ball up easily with such a tall face height and it's resulting higher center of gravity added in. In addition, a #3, #5, or #7 woodhead are what they are by virtue of their greater loft angles. Add these two points together and there is no way under the laws of physics the metal with the highest strength to elasticity ratio can ever push the COR and ball velocity as high as a driver. These shorter face and greater loft facts of fairway wood life are such that the performance of a good face alloy with a slightly lower strength to elasticity ratio such as 6/4 Titanium performs the same in a strong #3woodhead as the 10-2-3 Beta Titanium. The added plus is you get this performance for a lot less price, since the 6/4 titanium is much lower in material and processing cost than is the 6/4 titanium. 3) In the #5 and #7 fairway woodheads, this same group of factors that changes face performance is multiplied even more by the fact the #5 and #7 are always made with more loft. In this case the selection of a CNC machined, Carpenter 455 high strength steel for the faces delivers maximum ball velocity but for an even more economical price than if these higher loft woodheads were made with 6/4 or Beta Titanium. return to top 4. What is C.O.R.? C.O.R. is an acronym for Coefficient of Restitution. It is a numerical expression between 0 and 1.00 that ranks the energy conservation of the collision of two objects. For example, a C.O.R. of 0.00 means that in a collision between two bodies ALL energy is lost. Conversely, a C.O.R. of 1.00 means ALL energy was retained, and thus the collision is termed 'perfectly elastic'. In the collision between a clubface and the golf ball, the highest COR through to be theoretically possible by golf club engineers is about 0.890. The highest COR yet manufactured in a clubhead is about 0.860. In May 2002, the USGA put an end to a two year disagreement within the golf industry by imposing a COR limit of 0.830 for clubheads. For a golfer with a 100mph swing speed, the difference in carry distance with a clubhead with a 0.830 and 0.860 COR is 5.6 yards. For lower clubhead speeds, the distance difference is less. return to top 5. What is the difference between a variable thickness and uniform thickness clubface? Since 2000, some companies have elected to manufacture the faces of some of their woodhead models to be slightly thicker in the center than around the perimeter, or edges of the face as opposed to having the same thickness for the entire face area. In a clubface of uniform thickness, the maximum point of face deflection is dead center in the middle of the face. Impact at any position other than the geometrical center will result in less flexing of the face, and with it, a lower COR and lower ball velocity. By making an area of the center of the face to be slightly thicker than the area all around the edges of the face, the goal is to allow impacts that are in the center to slightly off center to still experience the same amount of face flexing. To make this premise successful, the face has to be designed in such a way so that the thin outer areas are thinner than what would survive impact were that thickness used in the center, but the center areas are thicker than what would be the minimum thickness required to survive normal impact with the ball. Computer modeling with an in-depth impact testing regimen are required to pick the right combination of how thick the center vs the outer edges of the face should be, how large the thicker area should extend out from the center, and how the transition of thickness change should be made. This is the reason the variable thickness face designs of the TWGT 915 and 545 woods were made by CNC machining and not simply by forging or stamping. return to top 6. What does the CrMo designation on the Wishon Model 725CrMo Woods Stand For? Cr and Mo are the chemical element symbols for Chromium and Molybdenum. The custom steel alloy used to make the true forged faces on the 725 woods has a specially formulated percentage of Chromium and Molybdenum in the steel, which is the key to the superior mechanical properties of this alloy. Typically, when the strength of a steel alloy increases to levels as high as the 300,000 psi yield strength of the S2C300 custom steel used to forge the faces of the 725 woods, the steel becomes more brittle and less elastic. As a result, when such alloys are made very thin to try to create a spring face design, the thin face can only deflect so far before the brittleness and low elasticity cause the face to crack. This is the primary reason that there are so few steel drivers made which come close to the USGA's 0.830 COR limit. TWGT's design experience with high strength steel alloys is extensive; to date we have designed the only steel face driver to exceed the USGA's 0.830 COR limit. The custom steel alloy used to forge the faces of the 725CrMo woods was created with our metallurgical advice to decrease brittleness and increase elasticity by reducing the amount of Chromium and increasing the amount of Molybdenum in the steel. return to top 7. Why are the Fairway Wood Lie Angles More Flat than the Driver Lie Angles on Most of Your Sets of Woodheads, When the Standard for Decades has been to make Driver Lie Angles more Flat than Fairway Woods? Drivers are used almost always with a tee, while Fairway woods are not. In addition, most people slice or push the ball with the driver more than they hit the Fairway wood off line because of the longer length and lower loft on the Driver. The more upright lie of the Drivers is intended to act as a minor aid in push/slice correction because the more the toe of the clubhead is up at impact (sole contact with turf more on the heel side of the sole), the more the loft angle of the Driver will cause the face to point to the left, thus slightly offsetting the slice/push problem. With a fairway wood it is much more beneficial for the center of the sole to be the main point of impact with the ball to ensure a center face impact. By making the Fairway wood lies a little more flat than the Driver, this aids in allowing the point of contact between the sole and the ground to be in the center of the sole. return to top 8. Why is the Face Thickness a Different Dimension for the Various Driver and Fairway Wood Models, such that some Drivers are Thinner than Other Drivers, or, some Fairway Woods are even Thicker than some Drivers? Face Thickness is determined by several factors – 1) material strength, 2) material elasticity, 3) face height/width, 4) loft angle, 5) bulge and roll – each which interact to affect each other. Therefore, the final face thickness is a combination of these factors times each other, or some 20 different relationships! Add in the fact that faces can be designed to be variable or uniform in thickness and you compound the determination even more!! TWGT has designed more thin face woodheads than any other company in the entire golf industry. The custom, computer modeling program developed by our Director of Engineering takes all of these factors into account to make its recommendation for what the face thickness should be to both survive wear and tear while maintaining the desired COR level. Here is a short version of how some of these factors are taken into account to determine face thickness. The higher the material strength the thinner the face could be. But as face area increases, the same material has to be thicker than if the face area is smaller. As the loft increases, the face can be thinner because the greater loft means less stress exerted on the face. As elasticity decreases, the face thickness for any strength material has to increase to prevent the face from flexing too much and permanently deforming. And as bulge and roll become more curved, the face thickness for any material strength can decrease, since the greater curve across or up and down the face resists the deflection of the face. As a result, it is possible that a Driver with normal face size made with a very high strength/high elastic material, can have a thinner face than a small face area Fairway wood made with a lower strength material, when normally you might think the much smaller face of the fairway wood should cause it to have a thinner face than the driver. Sound confusing? Not if you remember the relationship of each factor to each other, a job which for TWGT is given to the computer running the face modeling program! return to top 9. Why does the Bulge and Roll change, or, is not the same for all Drivers or the same for all Fairway Woods? Bulge is the horizontal curvature across the face of the woodheads from heel to toe, while Roll is the vertical curvature. Both are measured in INCHES of radius, and not degrees. Now that we have that point out of the way, our decisions on what Bulge and Roll are for any of the woodheads we design are made from a combination chiefly of the physics of the woodhead performance with a note toward the visual appearance of the face in the playing position. From the performance side, the actual bulge radius is determined by three things, first the distance the Center of Gravity (CG) is located in the head back from the face, second, the loft of the head, and third the width of the face from heel to toe. The farther back the CG is from the face, the more the bulge radius should be so as to react properly when the head rotates around its CG when an off-center impact occurs. The more the loft of the face, the more the ball skids up the face instead of sideways before taking off, and thus the less bulge radius is required on the face. And the wider the face from toe to heel, the more chance there is the golfer could hit the ball farther off center, given that golfers always use up more of their 'safety net' than what they should! Therefore, if too much radius is on the face, an off-center impact over 1 from the CG could cause the ball to start too far off line such that the natural 'gear effect' sidespin created from the head rotating about its CG might not be enough to bring the ball back toward the fairway. In addition, from a visual standpoint, the much larger driver head shapes that have become more popular today create a visual requirement to choose the bulge radius carefully. A 12 bulge on a 425cc driver head will look more rounded than it will on a 250cc driver because of the longer face on that larger head, a factor that some players might not be comfortable with looking at in the playing position. Another point to keep in mind about the design of the vertical Roll radius is that a woodhead does NOT rotate about its center of gravity in a vertical plan at all to the same extent it does on the horizontal plane. Some of our recent computer modeling studies performed in 2002 have shown that the shaft actually acts as a 'brace' so to speak, to restrict the vertical plane rotation of the head around its CG when impact occurs above or below the CG. In addition, woodhead dimensions are such that vertical face height is less than face width. That means when the golfer misses the CG at impact, the distance missed up or down from the CG is almost always less than what they can miss the CG toward the toe or heel. This causes much less of a force to rotate the head about its CG, so the amount of CG rotation in the vertical plane will be less. Add the fact that roll radius actually means more loft above the CG and less below, and that means golfers do not get the same launch angle from a mis-hit above or below the CG as they would in the center. As a result of all these points combined, we design less vertical roll radius on all of our drivers so as to offer a slight performance advantage when the golfer makes contact with the ball too high or low on the face. return to top 10. What is the best combination of impact launch parameters for a golfer? The answer depends on what the golfer wants to achieve in terms of distance vs accuracy. Since most golfers want both distance AND accuracy, the answer becomes even more difficult because certain launch parameters for distance when clubhead hits ball are in opposition to what is optimal for accuracy. For maximum distance, the golfer wants to achieve a combination of launch parameters that would deliver the highest launch angle with the lowest amount of backspin with the highest ball velocity AT THE SAME TIME. And therein lies the rub, as Shakespeare used to say. It is easy to increase launch angle by increasing loft, moving to a more rear-CG location in the clubhead, or using a shaft with a softer overall flex/softer flex tip section. But these changes on their own will also bring with them a decrease in the ball velocity and an increase in backspin at the same time. So the net result could be a loss of distance if the drop in ball velocity + backspin increase cancels out the increase in launch angle. Launch Angle is the easiest parameter for a clubmaker to change for a golfer and see immediate results in just the launch angle. Backspin reduction is the hardest because so much of that parameter is tied directly to the swing movements of the golfer, which at best require a lot of instruction and commitment to practicing the swing changes. That leaves Ball Velocity. What are ways to increase ball velocity at the same time you increase Launch Angle? A driver head with a higher COR than what the golfer is currently using is one way. Another is to switch to a more flexible shaft or more tip flexible (soft tip) shaft, because a change in shaft that also changes trajectory will not normally lower the ball velocity at the same time. It may add backspin but normally if the player is using a higher COR driver head AND has a higher launch shaft, those two factors will more than overcome the decreasing effect of the greater backspin. But never forget that because so many golfers with a driver swing speed under 90 mph are only generating ballistic ball flight, many times for these types of players a launch angle increase simply from a higher loft driver will keep the ball in the air long enough to generate greater carry distance. return to top 11. What do you mean in shaft design when you say Zone Technology or Bending Profile, as in the case of the Wishon design ZT Series and BP Technology shafts? For decades shaft stiffness was only measured by subjecting the shaft to ONE form of measurement. The predominant forms of single stiffness measurement have been Deflection and Frequency. In both cases the shaft is secured tight by the butt end with a known mass is attached to the tip. In Deflection stiffness measurement the distance the tip deflects from the butt is recorded. The shaft in which the tip deflects the greatest distance from the line of the butt is the most flexible, and the least deflection distance is the stiffest. In Frequency measurement, the tip with the mass affixed is set in motion to oscillate up and down. The number of oscillations is counted over a known period of time such that the higher the number of oscillations up and down, the stiffer the shaft – the lower the number, the more flexible the shaft. But long ago we noticed that it was possible to have two or more shafts with the same butt clamped deflection/frequency that played entirely different. As a result, we began to reverse the clamping position of the shaft and discovered that it was very common to see two or more shafts with the same butt clamp deflection/frequency but which had tip clamped deflection/frequency measurements that were quite different. From adding the number of places where we test for stiffness in the shaft, we began to see that shaft stiffness is distributed over the entire length of the shaft. In time we began to increase the number of clamping positions for the shaft so that we could take stiffness readings at 3, 4 or up to 10 different positions on the shaft. Once we did this, we were then able to use the measurements to create a drawing of the bending curve of the shaft. By overlaying one shaft's total bend curve over another it became possible to see some of the more precise ways that shafts can vary in their total bending stiffness from each other. Then, by applying experience from knowing golfer types that like or dislike shafts for which we plot the bending curve, it is then possible to create new shafts with specific bending curves, or bending profiles, for specific types of golf swing characteristics. And it is by using this type of analysis combined with our decades of observing the results of golfers using different shafts that we have created these ZT and BP, and LV ladies shafts in our proprietary TWGT shaft model designs. return to top 12. Why are some of your Driver designs made with Hook face angle while others are Square? Different strokes for different folks! Actually, because the vast majority of golfers who hit the ball crooked on a regular basis tend to push or slice more than hook or pull, when we create a Driver model that we believe is going to be chosen more by the middle to higher handicap player, we tend to design those models with a hook face angle, with the belief that face angle specification will satisfy a higher percentage of golfers. Then we follow the trend that the more accomplished ball strikers will generally prefer a slightly smaller head shape, and so on those driver models we tend to design the face angle to be square. No company regardless of size can design enough variations in driver size vs. face angle options to fit all golfers you may encounter in your clubmaking. Therefore, we do try to offer you options in face angle design that will allow you to be successful in your custom driver fitting the highest percentage of the time. return to top 13. Why are the Lady clubhead weight specifications heavier than the other clubhead designs in your line? Typically, ladies clubs in the past have been assembled to playing lengths that are 1" shorter than for men. However, in the past several years, the playing length of men's clubs has increased to the point that we believe ladies clubs should typically be assembled to be at least 1" shorter than the typical men's clubs. For example, 10-20 years ago the average playing length for a man's driver was considered to be 43" to 44". At that time, building the typical lady Driver to be 42" or even 43 was acceptable, keeping in mind that the longer the club length, the more difficult it will be to hit the ball on center a higher percentage of the time. Today, with men's drivers pretty much starting at 45", it is not at all wise in our clubmaking opinion to make most lady Drivers to be 44", unless the lady has the swing ability to deliver that length consistently back to impact. Therefore, by making the headweights of the ladies model clubheads a little higher than the men's headweights, we are in essence, 'telling' clubmakers we advise an assembled length not longer than 43". Thus the slightly higher lady clubhead weight will allow clubmakers to hit typical swingweight ranges for the ladies at this more advisable length. Additionally, the slightly higher headweight for the ladies clubheads along with the capability of our Swingweight Bore weight chamber also allows you to use light graphite shafts for the ladies and still achieve typical swingweight ranges in your assembly. return to top 14. What do the various numbers and letters that are used to describe metals in clubmaking mean? I mean things like 10-2-3 Titanium, SP700 Titanium, 455 Steel, and so forth? Some of it makes sense and some of it is the metal supplier/manufacturer's own brand name for the material. To start with, several countries have their own system of naming/classifying metals which can make this a little more confusing. For example, SP700 and DAT51 are both Japanese titanium alloys so the naming convention is from their country's system. Russia has their own system and so too does the US. The US system is somewhat more universally used and consists of the numbering system for which we are more conversant like 10-2-3 Titanium, 1040 Carbon Steel, or 17-4, 15-5, 431 Stainless Steel, to name only very few for example. In this nomenclature the numbers represent the amount of particular chemical elements that are a predominant part of the alloy. By no means does this system reveal ALL of the chemical elements in a metal, but simply the 'important' ones that account for the main characteristics of the material. The American Iron and Steel Institute, which inaugurated this system, uses a very clear, defined method of explanation for this nomenclature. In their 4-digit system for classifying all Carbon Steel alloys, which are most commonly used to make TRUE forged irons, the number 1 means the metal is a carbon steel. The second digit of 0 or 1 refers to the processing method for the carbon steel, which is not important for this explanation. The last two digits confirm the percentage of the element Carbon in the alloy, such that 1040 means the alloy contains between 0.37% to 0.44% Carbon in the mix. In the world of stainless steel, the numbering system you have seen to describe some of the popular alloys does directly represent the percentage of the key chemical elements in the material. For example, 17-4 means a steel with not more than 17% chromium and 4% nickel, 15-5 is 15% chromium and 5% nickel. But then, oops, there are deviations too, such as the case of 431 steel so commonly used for investment casting ironheads, where the alloy consists of 15% chromium and 2% nickel! In the world of titanium, clubmakers are most familiar with grades such as 10-2-3 (10% Vanadium, 2% Iron and 3% Aluminum), 15-3-3-3 (15% Vanadium, 3% Chromium, 3% Aluminum, 3% Tin) or 6-4 (6% Aluminum, 4% Vanadium). Again, each alloy's specific mechanical properties such as strengths or elasticity are largely ordained by the element make-up, so hence the reason for metallurgists to know these designations. Then you have the other organizations in the US such as the ASTM, or SAE and others, who have developed their own methods of nomenclature for similar alloys. Thus, at the end of the day, the only way you can really decipher a metal alloy name/code is to research the material and mechanical property specifications for each alloy from the company that made it. And MOST IMPORTANT for clubmakers to remember is that just because you see an alloy name listed with a particular clubhead design does not in any way assure that the head is either made with that alloy, that it is the best alloy for that specific shape and design, or that it the alloy has been processed properly for its use in that particular head design. While TWGT will never profess to know everything about metallurgy, we do believe strongly we know more about it from the sense of proper selection and processing for the designs we create than any other company in the component business. return to top 15. I hear the term 'Heat Treated' sometimes used in conjunction with presenting a particular clubhead design. What does that mean? After the metal is forged, cast or formed into the shape of the clubhead, by no means does that ensure that the material possesses the correct or even the stated mechanical properties associated with it. By mechanical properties, we mean things like the yield or tensile strength, the hardness, the modulus/elasticity, and many other characteristics of the metal. To achieve their final mechanical properties, most metals, after being formed into the part they are being used to make, must be further processed, most commonly by being placed in special ovens to be heated to precise levels of temperature over specific periods of time. In addition, any one metal can be heat treated in many different ways, depending on what the designer wants the final mechanical properties of his part to be. For example, clubmakers might be very familiar with the high strength steel alloy called Carpenter 455 that has been used to form the faces of a lot of metal woods in the past decade. In the strip form most commonly used to make a woodhead face from the 455 steel, if you simply weld the plate to the head with no heat treatment (as formed) the steel only has 135,000psi strength, is very stretchable at 18% elongation, and has a lower hardness of Rockwell C33. Not really a high strength steel at all! Interestingly, you can see how the application of specific heat treatments that only vary by 50 degrees F (and of course time of application is important) you see the final strength, elongation and hardness vary quite a lot. So the point is that heat treatment is ALL IMPORTANT to determining the final performance of virtually any alloy used to make a clubhead. Therefore, it is critical for quality that the clubheads you use for your clubmaking are designed and manufactured by reputable companies, because no clubmakers will ever be able to test the heads they buy for these properties. return to top 16. What determines how you choose the various dimension specifications for an iron design, such as toe height, heel/crotch height and blade length? The answer to this is again, a combination of the design performance intended along with the visual look of the clubhead when placed in the playing position behind the ball. TWGT designs all of its clubhead models to dimensions that we determine and specify to the foundry. In addition we do all of our designing in Metric specifications for dimensions because the progressions of size change from one head to the next are much easier to define in millimeters than decimal inches. A typical progression for the toe height from head to head in a set of irons is 1mm, for the crotch height it is 0.5mm and most often the blade length stays the same for each head in an iron set. We say typical, because there are cases we may progress by more or less or even keep certain adjacent heads in an iron set the same blade dimensions. The first design specification that ordains blade size is the headweight. Because irons are most typically assembled to incremental changes in length from the #1 to the #9-iron, the headweights do increase by 7 grams. (that too may vary depending on the intent for assembly by the designer) The 7g increase per head is what typically allows the swingweight to end up the same for each head when the clubs are assembled to changes in length. Because each ironhead is getting heavier, the main reason the dimensions increase is to establish more area in the head to accommodate the weight increase requirement. Of course, if the designer wants to deviate from the 1mm/0.5mm increase in toe/heel height from head to head, then the weight increase has to be picked up in some other dimension, such as sole width, face thickness, or the many other places in the head's design shape features. Using only the #5-iron dimensions as an example, an average #5-iron in a set of cavity back irons today would have a toe height of 54mm, heel height of 32mm and blade length of 80mm. Granted, there are #5-irons in sets today that range in toe/heel/blade dimensions from 50mm/28mm/78mm up to 60mm/38mm/84mm. What overall size is again, in the mind of the designer and what is intended in terms of looks and playability together. But obviously if all the #5-iron headweights are in the range of 250 grams to 264 grams (average is 254g) the bigger #5-ironheads have to thin out some dimensions and the smaller ones thicken some up, to allow the larger head size end up the same desired weight. Obviously, the Center of Gravity of each ironhead is an important feature to keep in mind when creating the blade dimensions for any iron design. Achieving the desired CG location for each head is a give and take task for the designer, in which some dimensions have to be increased or decreased in areas the designer knows will establish the desired CG location. return to top 17. Why do you design your iron sets with the headweight of the PW higher than the #9-iron? Typically, the PW has always been assembled to be the same playing length and swingweight as the #9-iron. However, today there are companies that make their PW 1/4” to 1⁄2” shorter, and in some cases a few swingweight points higher than the #9-iron. In other words, some customization of the PW compared to the #9-iron has become more common in clubmaking today. We establish the headweight of our PW heads to be 3-4grams heavier than the #9-iron to give clubmakers a few custom assembly options. If you choose to make the PW the same length as the #9-iron, using the same shaft and grip the swingweight of the PW will be about 2 swingweight points higher in the initial assembly swingweight Note that this does not automatically mean the FINAL swingweight will be higher because depending on the shaft weight, grip weight and desired final length, you maybe adding weight to the #9-iron anyway to achieve that final desired swingweight. In this case you still would have the option to make the PW the same length as the #9-iron AND still be the same swingweight. In addition, if you wish to make the PW to be 1/4” to 1⁄2” shorter than the #9-iron, the extra 3-4 grams of headweight in the PW gives you the option of making the swingweight the same as the #9-iron. From a fitting and playability standpoint, TWGT does recommend that the swingweight of the PW be made to be 2 swingweight points higher than the swingweight of the set. The reason is because most of the time and unlike the #2 - #9-irons, the PW is being swung at less than a full swing. When the PW is used for a three-quarters swing down to chip shots, a higher headweight feel can help make the rhythm of the slower and shorter length swing to be more consistent. return to top 18. What is meant by the term CP grade Titanium when referring to titanium alloys used in the manufacture of a titanium driver or woodhead? CP grade stands for Commercially Pure Titanium. While the name might conjure up an image of the best and most pure type of titanium, in fact what it means is that the titanium has not been alloyed, i.e. no other chemical elements have been added to change the mechanical properties of the metal. Therefore, CP grade titanium is the weakest grade of titanium metal, with yield strength in some cases well below 100,000 psi. Therefore, in no way can CP grade titanium be used for any part of the woodhead other than an area that will be under very little stress. CP grade is actually offered in 5 different grades of titanium, referred to as CP1 through CP5, with CP1 offering a yield strength of well under 100,000 psi and CP5 being a little above that strength level. CP grade titanium is much less expensive than any of the alloyed grades clubmakers are more familiar with such as 6-4Ti, 10-2-3Ti and several others. As a result, the makers of the lowest price titanium woodheads rely on using CP grades of titanium to make all of the body of the head, in the process saving enough in cost to allow the finished head to sell for a very cheap price, such as $40-$60. Whether CP grade can be safely used in the manufacture of a titanium woodhead depends on the design shape and size of the head. At TWGT, we only use CP4 and CP5 grades and ONLY for the top or bottom of a 3-piece or 4-piece construction titanium woodhead that is under 320cc in size. For all of our titanium drivers that are larger than 320cc, we switch to 6-4 titanium for the top shell piece because when a driver becomes larger than 320cc, there is a enough stress placed on the top of the head that even a CP5 grade would cause flexing and/or vibration that would absorb energy from impact and potentially reduce the ball velocity off the face. In addition, when we design a 3-piece or 4-piece titanium driver larger than 400cc, we specify that all of the parts of the body must be 6-4 grade to maximize the energy transfer to the ball. return to top 19. What is the difference between a titanium woodhead that is made from multiple pieces welded together compared to one that is made by investment casting, or forging? Currently in the golf industry, titanium woodheads are made in a variety of construction methods. 2-piece forged, 3-piece, 4-piece, 2-piece all investment cast, 1-piece investment cast body + plate formed face, 1-piece investment cast body + true forged face, are just some of the methods employed to make titanium woodheads. While a more thorough discussion of the various construction methods will be in a future White Paper on our web site, we can offer a few key points in this shorter response to the question. When titanium woods first hit the US market, almost all were made by 2-piece investment casting, with the face + body as one cast piece, and the soleplate piece being the other. Only a few foundries could make them because the cost of the vacuum casting machinery required to cast titanium was incredibly expensive. Demand being high for titanium woodheads all through the 1990s, the 3-piece and 4-piece construction method soon followed. The number of factories offering 3 and 4-piece titanium woodheads exploded, because the cost of tooling up to offer such a head was very low. 3 and 4-piece titanium woodheads are made by press-forming titanium sheet/plate material. In a 4-piece, the top plate, sole + sides, the face and the hosel comprise the four pieces. In a 3-piece the hosel is formed in one piece with the top plate, then joined with the sole + sides and the face to reduce the number of pieces by one. The key elements to a quality 3 or 4-piece titanium woodhead are all in the selection of the proper quality titanium sheet material for the design shape/size, and then heavily in the quality of the welding of all of the 4-pieces together to form the whole woodhead. (A little was said about the selection of the titanium plate material in the Tech FAQ about CP grade titanium. Refer back to that question, or dive into the White Paper about titanium head construction to learn even more) Welding titanium is a very tricky proposition because the material is extremely reactive to oxygen. Exceed the minimum oxidation threshold of titanium welding and the result can be cracking of the head at the seams when the club it used in play. In our career experience of designing more than 50 different titanium driver heads alone, and visiting many different titanium head-making foundries/factories, we have seen a lot of different welding methods employed by foundries, many which were very suspect in their quality. As a result TWGT will only contract with two factories to perform the welding of any titanium wood head we design, regardless of construction method. So the net result is that the difference between any of the methods of constructing a titanium woodhead is all in the design and then in the quality of the manufacture. 3 and 4-piece heads if made properly make as good of a titanium woodhead as there is, with the key on watchdogging the manufacturing processes closely. return to top 20. I see some woodhead models in the TWGT line where the face thickness of the fairway wood is the same or a little more thick than the driver. If the fairway wood is smaller in face area and has more loft, shouldn't its face thickness be less than the driver to exhibit good spring face capability? If the faces of the fairway woods are made from the same exact material as the driver, then yes, in a spring face design their faces should and would be thinner than the driver. For example, the Wishon 725CrMo set of woods are all made with the same new custom high strength true forged steel alloy called C2M300. So in this model the fairway faces are a little thinner than the driver. We have also designed many of our woodhead sets so that the face material changes from the driver to the fairway woods. For example in the Tamarron Grand Monarch woods, the drivers are both made with a forged 22-4 Beta Titanium while the fairway woods are made from investment cast 15-5 stainless steel. Because the 22-4 Beta Titanium has a yield strength and elastic modulus twice that of the 15-5, the faces of the drivers are thinner than the fairway wood faces. So the answer to the question lies in the strength and elasticity of the material used to make the faces of the woodhead. Higher strength and lower modulus of elasticity means the face can be thinner than if made with a lower strength and higher modulus material. Because TWGT has a tremendous amount of experience in designing, computer modeling and manufacturing thin face woodheads, we feel very confident in our ability to engineer the face thickness of any woodhead model to maximize its performance. return to top 21. Why does TWGT design sets of woods where the Driver and Fairway woods have different materials for the face? While we pride ourselves on being able to perform cutting edge design as well or better than any company in the entire golf industry, we also design with a sense of practicality and realism as well. Plain and simple, as long as fairway woods are designed so their face height is not much taller than 36-38mm, there is no way with any metal found on the planet that their spring face/COR capability will ever approach that of the typical driver. From our computer modeling of clubface performance we know that the height of the face and the total face area is the primary factor that determines to what extent you can push the spring face/COR capability of the head. Larger faces like the 45mm to 62mm face heights of today's drivers combined with sophisticated Beta Titanium and high strength steel alloys definitely allow the designer to push the COR limit of the USGA. But when you drop the face height down to the preferred size of fairway woods, you really drop the spring face/COR capability of the face. Yes, the fairway woods of the Wishon 915CFE and 725CrMo do have a higher COR than the fairway woods we designed for the other sets of woods in our line, and they provide a little higher performance. But they are more expensive because of that higher cost face material and not every golfer wants to pay the same amount or a higher price for the matching fairway woods in their set. As a result, we offer high performance fairway woods for those who want to push the performance of all their woods to the highest level, but we also offer very good performing fairway woods that match with very high performance driver designs for those golfers who want to economize a little in their wood set investment. return to top 22. What is the COR difference between a Driver and a Fairway wood, and the COR difference between a Fairway wood made with a high-tech alloy vs. a Fairway wood made with a conventional stainless steel alloy? Again referring back to the previous Tech FAQ, the face height difference between a typical 350cc or larger driver with a 53mm to 58mm face height and a #3 wood with a 36-38mm face height is vast in terms of spring face/COR. Today with proper material selection and the correct face thickness engineering, it is not that difficult to make such a driver hit the USGA's COR limit of 0.830. The highest #3-wood COR that we have ever encountered in our foundry COR test programs was a thin face beta titanium #3-wood with a 40mm face height that achieved a COR of 0.770. Most titanium and high strength steel face #3-wood heads would have a COR of 0.750. Typical COR for a 36mm #3 wood made from 15-5 Stainless Steel with the face thinned to the limit for the mechanical properties of the 15-5 steel is about 0.720. In terms of performance, the difference in ball velocity between an extreme #3 wood with a COR of 0.780 and a COR of 0.720 is 5 mph, which translates into 10-12 yards. Between a fairway wood of 0.750 and 0.720 COR, that difference drops to 5-6 yards. return to top 23. Why do you design some sets of woods with the Face Angle of the Driver different than the Face Angle of the Fairway woods? In many of the TWGT woodhead designs, it is true that we do intentionally design the face angle of the Driver to be more closed (hook) than the face angle of the Fairway Woods. The primary reason for this is the loft angle. The less the loft, the more chance there is of putting sidespin, or more correctly stated, the more chance the axis of spin rotation will be tilted, thus resulting in more off-line flight of the ball. Simply stated, the majority of golfers who suffer from mis-direction flight with the woods miss the fairway far more with the Driver, and then progressively less with the higher loft Fairway Woods. As a result, for a set in which we design the face angle of the Driver and #3-wood to be 1

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