MISCELLANEOUS
GOLF CLUB & SHAFT TERMINOLOGY
I have tried to define some of the most common terminology bantered about in the golf equipment community. Click on something that interests you, or page through the list.
Golf Terms Menu
Hosel
Pronounced "ha-zil", not like the rubber hose you use to wash your car. It is
that portion of an iron and wood club head into which a shaft is epoxied. The standard diameter of an iron hosel is .370 inches, while the standard diameter of a wood hosel is .335 inches. Shaft tips are produced to these diameters which is why an iron shaft will not fit into a wood hosel (the wood hosel is a smaller diameter than an iron!)
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Loft
Most everyone has some idea about loft, that is, the higher the loft, the higher the ball goes. Duh! But not everyone knows loft is measured differently for irons and woods. Loft on irons is measured as the angle (in degrees, remember geometry) between (a) the centerline of the hosel, and (b) the iron's face. Loft on woods is measured as the angle between (a) the sole line, and (b) the midpoint on the wood's face height, less 90 degrees. The reason for using the face's midpoint is due to the curve of the face from the sole to the crown known as "vertical face roll" which is on all woods, but not irons.
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Face Angle
Face angle is found on woods, expressed in degrees, and is best explained by (a) imagining a line from the target to your club head, and (b) placing your club head on the target line so the center of the shaft is perpendicular to the target line. If the club face appears to be aiming to the right of the target, the face angle is said to be "open". If the club face appears to be aiming to the left of the target, the face angle is said to be "closed". A club face that is perpendicular to the target line is said to be "square". Because of the club head contours, many club heads are produced 1 degree open to give the club a "square" appearance at address. Club heads with closed faces of 2 or more degrees are designed to help chronic slicers square the club face at impact.
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Center of Gravity
This is easy to understand if you have a physics degree, or are talking about a perfectly symmetrical object like a golf ball, whose geometric center is the center of gravity. It's a little more difficult with a non-symmetrical object like a club head. Also called the "center of mass" by science geeks, a club head's center of gravity (wood or iron) could be determined by:
balancing the club face on your finger, and then drawing a vertical line perpendicular from the floor through the club face, then
balancing the sole on your finger, and drawing a vertical line
perpendicular from the floor through the sole.
the intersection of these two lines, somewhere inside the club head, represents the center of gravity.
However, computer models are more effective than your finger, but you get the idea. The center of gravity is a lot closer the face in an iron than a wood, and the lower the center of gravity, the more solid the shot.
Some golfers think by putting lead tape on their club heads they are lowering
the center of gravity...No way Jose...You will change the swing weight, but in order to lower the center of gravity on your 5 iron 1/64" you would have to apply 15 one inch pieces of lead tape. The 5 iron would be unplayable...Don't believe me, try it..
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Gear Effect
When you hit a ball on the toe of the face, you usually feel it, telling you what a lousy shot you just hit. That's because the club head is trying to rotate clockwise around its center of gravity, which is to wards the center of the club head, as the ball strikes the toe. Now imagine the club face and ball having teeth like gears in a clock. As the club face moves clockwise, the ball will move (spin) counterclockwise, imparting a hooking effect on the ball. This is known as the gear effect. There is little gear effect on irons where the center of gravity is close to the face. But on woods, where the center of gravity is farther away from the face toward the rear, gear effect can be a factor. Club designers try to counteract the gear effect by designing a radiused face (known as "bulge") on woods. Now you know why wood faces have a curved look to them at address, while irons are horizontal or straight.
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Offset & Face Progression
Sounds like technospeak, and it is. You've probably heard or seen offset in
woods and irons, so let's address that first. Offset is the distance in millimeters, from the club face's leading edge (you know, where the face and sole of a club head meet), to the side of the hosel toward the target. The more offset, or greater this distance, the easier it is supposed to be to hit the ball. Offset helps keep your hands ahead of the club face promoting a more solid down and through swing. Face progression is the measurement from the club face leading edge, to the centerline of the hosel. But we have yet to see a club company market clubs with XX millimeters of face progression, so all you need to remember is offset.
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Progressive Offset
No, this is not a combination of "offset" and "face progression". Progressive
offset refers to the amount of offset throughout a set of irons. In a set of irons with progressive offset, the three iron will have the most offset, while the PW has the least. Such an iron set may go from 1mm offset on the PW, to 5.9mm on the three iron, that is, the offset "progresses" through the set. Get it, progresses? Who thought of this?
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Stainless Steel Types: 17-4, 431, 15-5
Differing types of stainless steel are used in club heads, and these types are referred to as 17-4 stainless, 431 stainless, and 15-5 stainless. 17-4 and 15-5 are used for woods and irons, and are "harder" than 431, while 431 is primarily used in irons. While they do have different metallurgical properties, hitting tests have shown no performance difference. Tests by blindfolded golfers substantiate no difference in "feel" between the three types, and claims to the contrary are victims of effective marketing. The difference between 17-4, 431, and 15-5 is analogous to the difference between oak and maple, they're both hard woods with subtle differences. It is not Styrofoam versus plastic!
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Alloys
While stainless steel and titanium are the preferred metals for quality club heads, alloys are equally effective in making the ball go. The most common alloy club heads are made of zinc, in the case of irons, and aluminum, in the case of woods. The principle differences between stainless steel club heads and alloys are (1) the metal hardness, and (2) quality in manufacturing process. Alloys are softer metals, so they scratch easier than stainless steel making alloys look pretty ugly after a couple rounds. They also bend easier, so it's not uncommon to have a zinc 5 iron bend after hitting a tree root changing the loft to a 3 iron. Alloys are not manufactured to the same exacting specifications that stainless steel is. Club head weights, lofts, lies can be way out of spec with alloys, some of which has to do with the manufacturing process, a whole different discussion. In summary, alloys are fine for beginners, even recommended to save $$, but look to stainless for better quality, better lasting club heads.
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Lie
Most people think the "lie" of a club head is the claim that club companies make when they tell you it goes farther and straighter than their competition! In fact, it is a measurement of how the club head "lies" on the ground from toe to heel. The measurement is taken by determining the angle in degrees (remember those protractors) between (a) the centerline of the shaft, and (b) the ground with the club head resting on its center. Get your buddy to stand at address with a club, and stand looking at the club face such that he would hit you with it. If the toe is raised up in the air, more so than the heel, the lie needs to be adjusted to a more "flat" lie. Danny DiVito probably has a flat lie. If the toe is touching the ground, it needs to be adjusted to a more "upright" lie, that used by David Robinson (San Antonio Spurs). Lie is affected by how you hold the club as much as height. Unless there is a dramatic "toe up" or "toe down" look, you need not worry too much about lie.
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Club Length
Off the rack golf clubs are made to standard lengths for men and women. Just what is the "right" length is dependent on many factors: height, arm length, ball striking ability, strength, etc. Longer lengths have become more popular to generate more club head speed to hit the ball farther. But if you can't control the club, the only benefit from additional length are the nature walks you'll take looking for your ball in the woods. Correctly fit and made golf clubs like you get here at Tommy Knocker Golf guarantee the correct length for each individual.
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Club head Weight
Club heads are produced to specific weights measured in grams, at least the quality heads are. This is because head weight is a factor in determining swing weight discussed here as well. Unlike human beings, the size of the club head does not reflect its weight. A five wood head weighs more than a driver, yet its overall size is smaller. Most golfers are not aware that all 5 irons weigh the same, all 6 irons weigh the same, all 2 irons weight the same and so on....The difference they feel between , lets say different 5 irons, is the "total weight" which is caused by the different shaft weights, not the head weight.
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Club head Volume
Everyone wants to know the volume of their woods these days, particularly those into the "bigger is better" thinking. Pull out your old chemistry book for the definition of volume. For club heads, volume is measured in cubic centimeters, and you could determine it by placing your driver head in a beaker of water, thereby measuring the water displaced and translated into cc's. But that's a lot of work, so ask your component supplier if ya just gotta know.
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Butt & Tip of Shaft
The butt is the end where the grip goes (Hey! watch what you're thinking), the tip is the skinny end where the club head goes. Tipping a shaft refers to cutting off the tip end, butt cutting a shaft refers to, well, you get it.
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Swing weight
Oh boy, this is a tough one. It is hard to explain and understand. The first thing you must get in your head is..Swing Weight has absolutely nothing to do with the weight of a golf club, only how the weight is distributed and how heavy the head end of the club feels when you swing the club..
There is a mathematical formula to figure the swing weight, but trust me you don't even want to see it. To find out the swing weight you have the club measured by putting it on a swing weight scale. This scale compares the ratio of weight at the head end to the weight at the grip end and gives the results to you in a "letter/number". (see below) A 12 pound golf club and a 1 pound golf club can both have a swing weight of D-1 if their weight is distributed the same. Ralph Maltby defines it as" the measurement of a golf club's weight about a fulcrum point which is established at a specified distance from the grip end of the club", which is a pretty good nontechnical description. I prefer this: how the club feels when you swing it - heavy, light, or just right!
The swing weight scale measurement is in "swing weight points" which is an alphanumeric range of 77 swing weight points, starting at A0, then A1, A2, etc. to A10, then B0, B1, and so on until reaching G10. A0 would be the "lightest" swing weight, G10 the heaviest. Most mens clubs are produced to have a swing weight of D0 or D1, which has become the standard, meaning a D0 or D1 swing weight feels not too heavy, or too light (during the swing), but just right for most men. Women's standard swing weight is about C5 to C7. This is a lot to swallow, so to understand how you can change the swing weight, go to Club Weight below.
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Club Weight
It is just that, how many ounces does the total club weigh. But total club weight does not determine swing weight. What does matter are the weight of the parts (head, shaft, grip) and the length of the club. These determine swing weight. Simple physics, right! More weight in the head, with less in the shaft and grip yields a higher swing weight (The heavier the head feels during the "swing"), and vice versa. The longer a club, the higher the swing weight, and vice versa. Try adding lead tape to your driver head, then take it off and add it to the grip and feel the difference in swing weight. The same is true swinging a 50" driver versus a 42" driver, big difference in feel or swing weight. Now you know why club head weight is important. With the varying weights of shafts (45 to 139 grams), grips, and lengths these days, swing weight becomes all the more complex. One axiom in golf is that one swing weight point is equal to the weight of a one dollar bill..NOT..try a dime you'll be closer. Tape a dime to the head of your club to see what one swing weight more feels like or two for two swing weight points and so on....One other false hood I'd like to clear up...Don't even believe by adding weight to the club head you can lower the center of gravity "Ain't even gonna happen". In order to drop the center of gravity 1/64" you would have to add over ten 2 gram pieces of lead tape to the bottom of the club head. It would be unplayable. Tape 30 dimes to the bottom of you club and you will understand .
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Frequency Matching
Someone dreamed this up who obviously had a perfect swing, leaving his equipment the only thing to improve upon! Frequency matching is beyond the simple discussion I would like to convey without boring you to death. Simply stated, frequency is a measure of stiffness determined by vibration cycles as a function of time (simple, right!). Imagine clamping a club in a machine at the grip end, bending the club head down, then measuring how much it vibrates up and down in a minute. This is known as cycles per minute, used to measure frequency. The objective is to get all your clubs "in tune" with the frequency difference from club to club the same. This way whacking a tree with your 5 iron will vibrate the same as hitting it with your 8 iron. There are several frequency machines and methods, but it really is a great tool for tuning golf clubs so they are flexed and feel the same through out the set.
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Ferrule
Pronounced "fair-ill", or as the say in Kentucky "fur-ill". These are the little plastic rings that come in all sizes and styles that fit over the shaft and rest on top of the hosel. These are mainly cosmetic, but do add some stability to graphite shafts preventing breakage. They will not do anything to make you a better golfer, so pick one you like to go with whatever club head you are assembling. Make sure you get iron ferrules for iron shafts/heads, wood ferrules for wood shafts/heads.
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Grips: Ribbed & Round
Most grips come in two styles, round and ribbed. A ribbed grip would be more
appropriately called a "spine" grip, because like your spine, it runs from the top of the grip to the bottom. On a ribbed grip, you will feel a ridge, or rib, or spine, running along the under side of the grip as you grip the club. This is supposed to assist in club head alignment, or make sure you do not address the ball with the club upside down! Installing a rib grip requires correct alignment or you'll get all messed up at address. A round grip has no rib, and you can mess up installing it without jeopardizing alignment. Which is for you is a matter of personal preference.
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Grip Cores
The core of a grip is that big cavity that the shaft goes into. Every grip has a core size expressed in inches. So a .600 grip has a core of .600 inches. If the butt diameter of the shaft you are gripping is the same size, then the end result will be a "standard size grip". If you put a .600 grip on a .580 shaft, the grip will be under sized by about 1/64". If you put a .580 grip on a .600 shaft, the grip will be over sized by about 1/64". Grip size is critical. If you re grip your on clubs do it right or get club maker that can measure your hand and make the grip fit the hand.
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Shaft Flex
In lay mens language, how much does the shaft bend when you swing it. Another way of defining it is as the relative stiffness of a shaft, or measure of a shaft's flexibility relative to a specific standard. And therein lies the problem. While the industry has established five basic flex types (X extra stiff, S stiff, R regular, A flexible, L ladies), each shaft manufacturer or club company has there own method of determining what makes an S flex, R flex, etc. In other words, True Temper's R flex might be the same as what Callaway calls an S flex. This makes comparing apples to apples in shafts quite difficult. Along comes Golfsmith and does something intelligent for a change. They tested and rated almost all the golf shafts on the market and assigned them a MPH rating. Now, finally club makers like myself can,given a golfers tempo and MPH of their swing , build golf clubs that are the exact flex for their swing.
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Measuring Shaft Flex
There are two ways. The first is using a shaft deflection board. Simply stated, this is a board with a graph on it whereby you clamp the club/shaft at the butt end, hang a weight on the club head or tip end, and look to see how far the shaft bends down. The other method is using a frequency machine (see frequency matching). There is no comparison between the two methods, the frequency method is the only way to get exact flex measurements.
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Shaft Flex Point
While the shaft flex theoretically tells us how the shaft will bend during a swing, the flex point, or kick point, or bend point (All the same) as some refer to it, is the point on the shaft where it will bend the most. The closer the flex point is to the tip (low flex point), the tendency is for a higher ball trajectory. The opposite is the case for high flex point shafts (closer to the butt, low ball trajectory). This is a bunch of crap...Golfsmith tested the kick point on almost every shaft made and guess what? They all fell with in a a 1 1/4" length of the shaft. They made identical clubs with the lowest kick point shaft and the highest and the difference in trajectory of the two clubs was "ONE DEGREE". Chalk another one up for hype. Don't get hung up on flex point. It has more to do with feel than trajectory. So, if you want a club to feel firm at the tip when you hit the ball, use a high flex point shaft or a low flex point to achieve a soft feel.
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Torque
This was a great marketing scam when graphite shafts were first introduced. It is supposed to refer to torsional stiffness, measuring resistance of the shaft to twisting (hold the club by the grip, get your friend to try to twist the head off, that's torque). The lower the torque, the less twisting and the more Aldila could charge you. This probably had some merit in the early days of graphite shafts which were more like fishing rods. Today, materials and manufacturing processes have improved such that torque is meaningless unless you swing like John Daly.
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Modulus
Like torque, this is more marketing today than anything else. Modulus (unit stress divided by unit strain) referred to the type of graphite material used to produce a particular shaft. The higher the modulus, the stiffer the material and the more you pay for the shaft. Technology has improved making modulus a non-factor, unless of course you sell graphite shafts!
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Parallel Unitized Shafts
This is the way most shafts are made today: one constant diameter from the tip to the first step, or for a certain length as on graphite shafts. You can use one shaft to make all your irons, one shaft to make all your woods, simply by cutting certain amounts off the tip of each shaft.
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Combination Shafts
These are parallel tip that can be trimmed from the tip to make one of two
flexes. For example, tip trim 2" to make a stiff 5 iron, or tip trim 1" to make a regular flex 5 iron.
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Taper Tip Shafts
The tip looks like the end of a pencil. Naturally, the hosel must be the same shape. For the most part, these have been replaced by parallel tip shafts, except for such hold overs as Ping, Powerbilt, Tommy Armour, and a few others who have not changed with the times (they want to sell you re shafting services).
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Countersunk Hosel
Countersunk, coned, or chambered all mean the same thing, material removed from the inside top of the hosel so they can be used with graphite shafts. Otherwise, the sharp hosel edge can cut into a graphite shaft layers, causing the shaft to break and your club head to fly in the pond.
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Roll & Bulge
Metal woods are designed with what are called "roll" and "bulge" on the face. Looking down on a club head, notice there is a curve, or radius, on the face from toe to heel. This is call "bulge". Bulge helps reduce gear effect which is exacerbated because the center of gravity is farther away from the face than on an iron. There is also a curve, or radius, from the top of the face (by the crown) to the bottom of the face (by the sole). This is called "roll", and is one of those things that designers put there because "that's how it's done". Too much roll will make the ball go higher on above center hits, and lower on below center hits. Your club would work without roll, but probably look goofy, so don't worry about it. No one else does.
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Hosel Bore Types
When discussing wood hosels, three different hosel bores are available:
1..Standard Bore...Usually in metal heads, the depth of the hosel is between 1 1/4 - 2 inches deep. This is the depth the shaft fits into the hosel.
2..Thru Bore...This is when the hosel hole goes all the way tru the sole of the club head. Calloways are renowned for this.
3..Blind Bore...Wooden heads and some composite heads have a hosel bores
that extent to within 1/4 inch of the sole plate, but do not go completely through. This hosel bore depth is usually around 4 inches.
It should be noted that the amount of tipping for the same shaft and flex will be different for each of these different types of bores.
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