cycles per minute (CPM)

Golf Terminology: Cycles Per Minute (CPM)

Golf Shaft Cycles Per Minute (CPM)

What a frequency analyzer machine does for golf

For many years a golf shaft’s stiffness was determined by using a flex board. This was a simple device. The flex board allowed the shaft butt to be hooked under a fixture at one end of the vertical board. The tip end then would have a weight hung on it, which caused the shaft to bend into a profile that could be measured against the flex board. So, you got a view of the shaft under stress to see if the butt was firm or the shaft had a weaker tip.

Most importantly, though, the board showed what flex range the shaft fell into, such as if it was a softer ladies (L), senior (A), regular (R), stiff (S) or extra stiff flex (X).

With the invention of the frequency analyzer machine, the time consuming task of using the flex board was not as important. Now club makers could get a fast, accurate reading of a golf shaft by checking the cycles per minute (CPM) the shaft would vibrate.


The frequency analyzer works by clamping the butt end of the shaft in a fixture and then twanging or plucking the tip end. The tip is bobbing up and down through a light source (usually a type of photo-electric eye) and produces CPM readings of the shaft. A cycle is created each time the shaft tip goes through the light beam. 


Here’s an illustration of this:

Take a ruler and place 1 or 2 inches of one end on a flat surface like a desktop. Hold that section down firmly. Let the remaining length hang off the desktop. Twang the ruler tip and you will see the body of the ruler bounce up and down. Note the speed it moves. Now increase the section that you are holding down where it is now about 3 to 4 inches. Go ahead and pluck the tip end again. You’ll see that the ruler now has a much faster vibration (Therefore, it is stiffer.).

The frequency analyzer also can tell you if a shaft has a slightly stiffer or softer side to it, depending on which way you orient the shaft in the machine. Due to the manner that steel shafts are manufactured, the tubular steel shafts tend to be very uniform in flex no matter which way you position the shaft in the fixture.

Composite graphite shafts, when manufactured in a professional manner, are also very uniform. However, some cheaper graphite shafts may have what is known as a “spine.” This is a slight overlap or opening in the way the composite materials were laid up during production causing either a slightly firmer or softer rib that runs down the length of the shaft.

Check out online writing papers service. You get only the best work in time.

Some shaft companies go to the trouble of identifying the location of this spine and mark it for the club maker. What seems to be a continual bone of contention is what to do with the knowledge of where the spine is located. Some folks believe that it should be positioned down the back of the shaft at assembly, while others think it should be oriented on the left or right side of the shaft. The USGA — golf’s governing body — has a rule that says that shafts must flex uniformly in all directions. But the USGA does allow club makers to position the shafts a certain way. This tells me that the USGA doesn’t really think all this effort to identify the spine produces much of a difference in accuracy.

Here is a basic formula your average golfers can use to determine what kind of flex they should have on their shafts. The diagram below gauges flex using driver swing speed matched with what particular club one uses from 150 yards.

X-Stiff; 105-plus, pitching wedge.

S-Stiff; 90-104, 8- or 9-iron.

R-Regular; 80-94, 6- or 7-iron.

A-Senior; 70-85, 5-iron or less.

L-Lady; 70 or less, 5 iron or less.





Golf Terminology: Characteristic of Time (CT)

Measuring a Clubface’s Characteristic Time (CT) or Flexibility and Spring-like Effect

And how the precise method replaced Coefficient of Restitution (COR) in overseeing golf clubface manufacturing and performance.

In the past, golfers with wooden clubheads would gather around the bar after their round and tell tales of how much more distance they were getting from the smokin’ face inserts in their drivers or favorite fairway woods.

Inserts with metal “firing pins” milled into the face, aluminum inserts, or the mythical “gamma-fire” glass insert were all part of the lore. Whether they actually worked or not is still debated, but since very few folks still swing persimmon clubheads we’ll skip that debate today.

When metalwoods became the norm, golfers became obsessed with how far a thin face could hurtle the ball. Manufacturers began making faces thinner and thinner until they were barely able to sustain the impact of a fast-swinging player.

However, distance was improving — and this concerned the USGA.

For several years, the USGA had used Coefficient of Restitution (COR) to identify how “hot” a clubface was. There was a cumbersome method of measuring that started by detaching the clubhead from the shaft, mounting it to a fixture and then firing a golf ball at it from an air cannon to get a reading on the COR.

You may remember that COR means how much energy is maintained after the golf ball (fired from the cannon) strikes the club face. A Perfect COR would be 1.0. The max spec set by the USGA was.830 COR. Anything over that was deemed non-conforming to the Rules of Golf.

Now the USGA uses a different method of measuring this spring-like effect. It is called the Characteristic Time or “CT.” You can click HERE to see the full USGA rules on measuring CT. 


Much easier and less expensive, it measures in microseconds (with the symbol: µs) the dwell time of a steel pendulum device as it impacts the clubface. The assembled club’s shaft is clamped into a fixture and the pendulum is adjusted to allow it to strike the center of the clubface.


Right from the USGA rule book on measuring CT or clubface flexibility.

The specified limit allowable is 239 µs, with a max tolerance of 18 µs, thus equaling a maximum CT of 257 µs.

There is said to be a correlation between COR and CT, but CT is a much more precise way of measuring the spring-like effect of a clubface.

The USGA seems to have tight reigns on the speed that it will allow manufacturers to produce on clubheads. This will further limit just how hot a club face may be and perhaps begin to put a cap on the distance golfers will hit the ball.

Ah, but don’t worry too much. I’m sure that the golf ball makers will be able to squeeze out a few more yards from the clubs when max CT is reached.


Players Versus Game-Improvement Golf Clubs

Golf Terminology: Players Versus Game-Improvement Golf Clubs


Golf Terminology: Players Versus Game-Improvement Golf Clubs

How much you play and practice the game of golf will influence what type of equipment you may choose to put in your bag, whether it be players or game-improvement golf clubs. 

A combination of lots of practice and play, understanding your game and the science behind it all figure into deciding what to choose — or when to switch.


If you play only occasionally or find that you need a little help with your shot making, you may elect to use game-improvement clubs.

I’ll define these as having the following features and benefits:

The driver and fairway woods will always have graphite shafts, usually with a little extra torque to allow you to feel and flex the shaft and help launch the ball higher. The clubheads also may have some extra loft. To help limit the tendency to slice the ball, the face angles may be a touch closed.

The irons usually will have a slightly larger clubhead from heel to toe versus a players’ club. They will have a somewhat wider sole with some bounce to help the club glide through the turf. The wide sole also creates a lower center of gravity (CG) in the head that tends to help get the ball up in the air.

Game-improvement irons always will have extra perimeter weighting, usually with additional heel-toe weighting. (Although, some game-improvement clubs may be designed like a hollow iron, similar to a hybrid head.) The conspicuous deep-cavity perimeter weighting acts to increase the moment of inertia (MOI).

A club with a higher MOI will resist rotating about its axis. This is very helpful when, in those rare instances, you miss-hit the ball off the heel or toe portion of the clubface. Since the head is designed with a higher MOI, your shot will not wander as far off-line.

Finally, game-improvement irons usually are designed with additional hosel offset. This helps place the hands ahead of the leading edge of the club head to aid the golfer in hitting down on the ball — which helps get the ball up.


Let’s now take a look at what a players club has to offer. These clubs tend to be for golfers that play the game substantially more, and at a higher skill level, than the average golfer. Golf professionals and lower-handicap players are the target market.

Their clubs will have these features and benefits:

The driver and fairway woods almost always are built with graphite shafts. The shafts will be designed with stiffer tips and lower torque, so the clubs may be swung with greater speed and accuracy. The clubface angles will tend to be square to open versus the game-improvement woods. This open face helps the stronger golfer swing more freely without fear of duck hooking a shot.

The players irons also have a shorter head length from heel to toe. The soles are generally narrower and blade-like with much less weight concentrated toward the bottom of the club when compared to a game-improvement iron.

Since the better player is much more adept at striking the ball on the sweet spot of the club face, he actually prefers an iron with a lower MOI. He also wants the low-torque steel shafts in his irons. All of these features allow the skilled golfer to manipulate the clubface and hit a variety of shots, from soft high fades to boring low draws.

The players club may have a little bounce, but the sole usually has a radius camber that performs the task of digging less into the turf. Skilled players already tend to hit down on the ball, so the hosel offset is usually far less than is seen on a game-improvement iron.

In years past, players irons generally were what we called “flat back.” That meant that the back of the head had no cavity of any kind. The head may have had only a slight muscle back or small sole flange. (It is interesting to note that early Scottish irons had “mussel” backs due to the shape of the bivalve mollusks the Scots ate. Years later it was changed to “muscle” to denote a powerful club design.)

Over the years skilled golfers noticed how much easier a cavity design was to hit and they began asking for this feature on some of their clubs. Nowadays, a players club, more often than not, may come with a slight cavity to make the game somewhat easier for even the best players.

Switching clubs rarely easy, Ask Rory

How-To Guides: Switching Golf Clubs Rarely Easy, Ask Rory

Switching clubs rarely easy, Ask Rory

How-To Guides: Switching Golf Clubs Rarely Easy, Ask Rory

When Even the Pro Golfers Change Equipment

When Rory McIlroy signed his deal to represent Nike Golf much was made — and is certainly be said after this weekend — about the adjustments he would have to make as he transitioned into Nike clubs.

Would he still be as good a golfer as he was before the switch? Did he do it just for the money? Since it has been reported that he signed a 10-year, $200 million deal, I have to assume that money played at least some part in the change. Although it didn’t stop him from bending a Nike 9 iron in apparent frustration last year at the US Open.  

Still, Nike clubs have always performed well for Tiger Woods and the rest of the Nike roster, so McIlroy should know that his less-than-stellar 2013 may be at least partially his fault.

The fact is that professional PGA Tour players are a lot like you and I. They come to rely on their equipment and have certain favorite clubs. Even if their new clubs are made perfectly to fit all their specs, the player still may not feel entirely comfortable.

And these professional golfers are exponentially more sensitive to their sticks — from shaft frequency, head shape, face angle and sound to the difficult to quantify “feel.”

But they are still like most golfers — always looking for something slightly better. Or in the case of the top pros, willing to take a chance for a big contract.

I have been fitting and making equipment for some of the top players in the world for more than 30 years, and I can tell you one thing: It is always a surprise what comments you get from the players.

“I love the new driver,” they’ve said, even though you know the composite shaft that was put in is different from the old one.

“I don’t like the look of the new putter,” I’ve heard, even though it was crafted to exactly match the previous stick.

“The leading edge needs to be softened more,” I’ve been told, even though the measured radius is rolled more than a tournament-winning previous set of irons.

“These feel light,” it’s been said, when you know the clubheads were ground to weight and swing weighted perfectly with shafts. Shafts that were sorted and weighed exactly to his specs.

In every case I’d make some adjustment to be sure that when he went into battle, the player knew his clubs were perfect for him.

Psychologically fitted?

Maybe you could say that. Sometimes you just can not get it right for the player. I worked with one Hall of Famer
in years past that was and still is one of the nicest gentleman you would ever hope to meet. Yet after multiple attempts at making clubs for him, he was never really satisfied.

Conversely, I have had another top, major winning pro that saw a set of irons that I was working on for someone else and immediately took a liking to them. He used them for many years on the PGA Tour.

Other golfers are perfectly satisfied with their clubs, as long as you annually check their loft and lie and maybe put on a new set of grips — although this example is rare.

Two legends of the game, Ben Hogan and Jack Nicklaus, had certain little things that had to be done to their drivers.

Ben Hogan during his historic 1950 US Open. Hogan won on a three-way 18-hole playoff.

At the Ben Hogan Golf Company, Hogan always insisted on having a small brass “shaft tip locking screw” installed in the through-bore tip of his steel driver shaft. This went back to his days at MacGregor Golf in the 1940s to the early 1950s when glue was not quite what it should have been (before epoxy was invented). The screw helped keep the shaft from coming out of the wooden head. Even years after epoxy was perfectly suitable to install a shaft, Hogan still wanted that little screw.

He said that it made the club feel better balanced. I know that when we made his driver, we always had to factor in that small screw to hit the swing weight he wanted.

Jack Nicklaus also had started with MacGregor early in his career, and his first professional driver had a butt weight of lead in the grip end of the shaft. This was a common way for mass-produced clubs in the 1960s to be counterbalanced and swing weighted with persimmon wood heads that were slightly too heavy.

Jack Nicklaus in 1976 at Glen Abbey Golf Club, the site of more than one of his Canadian Open losses.

We would never do this for professional Tour players, but Nicklaus’ favorite club was built that way — and he continues with this method of butt weighting even today.

So, in a way, even the supposedly most-rational weekend golfer can be compared to an all-time great.


Golf Basics: The Grip

How-To Guides: The Golf Grip

Golf Basics: The Grip

How-To Guides: Golf Basics: The Grip

Golf’s fundamentals begin with your grip

Any good player will tell you, the start of a new season is a time for refocusing on fundamentals. Be it a low-handicap amateur, a PGA teaching professional or a touring pro playing for millions week in and week out — they all will focus on the basics when coming back from a long layoff.

Posture, alignment, tempo, ball position. Fundamentals are the foundation upon which your swing is built, and if they’re not solid, you won’t be either.

Perhaps the most important of these fundamentals is the grip. The hands are the only point of contact between you and the club; they control everything. It’s also not impossible to play quality golf with a strange grip.

Paul Azinger is fond of telling the story of how Nick Faldo describes him as having a “homemade grip with a hatchet swing.” And Azinger won a PGA Championship. But you’re certainly increasing your degree of difficulty if you don’t take the time to learn a fundamentally sound way to hold the club.

Thankfully, it’s also a comparatively easy thing to get right. The biggest mistake most amateurs make with their grip is holding the club too much in the palm of their left hands, as if it were a baseball bat. Baseball is a fine game, and a sport I love dearly, but the baseball swing is an act of controlled violence, a heavy chunk of maple or ash wielded with brute force. Golf clubs are lighter, more precise. The golf swing an act of tempo, rhythm, and control.

That’s a responsibility you want to give to the finer motor controls of the fingers.

Start by aligning the butt-end of the club along your glove hand on the bottom third of your pinkie finger, below the knuckle but above the palm. This will set up everything else about the grip. If you have the club positioned well in your pinkie, there’s no way to end up with a palmy, baseball-style grip.

Close your hand comfortably around the club. If you take your stance and address a ball from this position, you should see roughly one and a half to two knuckles on the top of your glove hand, with the “V” formed by the line between your thumb and forefinger pointing towards your right shoulder (left shoulder for lefties). 

If you’re a beginner, you’ll probably want to rotate your glove hand a little more so that you see somewhere between two and a half and three knuckles. This is referred to as a “strong” grip, helping you close your clubface at impact and produce a left-to-right (or right-to-left for southpaws) drawing ball flight that results in more distance.

Lower handicappers will generally stay with a neutral grip, or in some cases go with a one-knuckle or “less-weak” grip to help produce a fading left-to-right (right-to-left for southpaws) ball flight for more control.

Once you’ve got your glove hand situated well on the club, place your non-glove hand on the club, making sure to once again keep the club running along your fingers and out of the palm. Your non-glove thumb should wrap comfortably over your glove-hand thumb, the “V’s” between thumb and forefinger running parallel to each other and, again, pointing at your right shoulder (left shoulder for lefties).

Your non-glove pinkie finger can connect with the glove hand in a number of ways. I prefer what’s called the “interlocking” grip (See Tiger Woods above.), where the index finger of the glove hand and the pinkie finger of the non-glove hand wrap around each other, firmly connecting the hands in a unified hold. Both Woods and Jack Nicklaus use the interlocking grip.

There is also the “10-finger” or “baseball-style” grip, in which the hands aren’t connected at all, with each finger resting consecutively along the club.

The most popular grip, however, is the “overlapping” or “Vardon” grip, named after British golf legend Harry Vardon, who popularized it. Here the pinkie on the non-glove hand rests on top of the glove-hand index finger. Most players prefer this grip because it allows for a feeling of unity with the hands, but still keeps the glove hand in charge and allowing for crisper contact at impact. 

There is no wrong choice when it comes to deciding between each of these styles, however. Go with whichever option feels the most comfortable and gives you the most control of your golf ball.

Finally, perhaps the most important part of having a good grip is maintaining light-grip pressure. You want to be able to hold the club securely, but keep your hands loose and free-flowing in order to avoid tension. Tension in your hands will lead to tension throughout your golf swing, sapping your clubhead speed, destroying your tempo and inevitably sending your ball far off-target.

Relax your hands and it will relax every other part of your game, allowing you to play your best.

A fundamentally sound grip is an easy thing to overlook, but it is the root cause of countless other problems in the golf swing.

Take the time at the beginning of a season to ensure that your grip and other fundamentals are rock-solid, and you can dive into the summer fully ready to play your best and attack the course.


Buying an Iron Set

How-To Guides: Buying an Iron Set

Buying an Iron Set

How-To Guides: Buying an Iron Set

Golf season is here, and everyone is thinking this will be the year for dropping the handicap. The right set of irons — and consistent practice and play — can definitely help you achieve that goal.

Now, most golfers golf bag consists of 14 clubs built for various reasons. What most people need to realize is that it takes just one decision, what iron set to buy, to influence a golfer’s entire set of clubs.

So what I recommend involves a simple three step process: Research; Consultation; Fitting.


Before you even enter a store, search around a few manufacturers’ websites to learn a little about the latest and greatest iron technology on the market. Read some online reviews, such as from 2nd Swing Blog’s comprehensive and free search archives, to help you figure out what kind of iron may match your skill level, club needs as well as playing goals, such as adding loft, feel, flex and distance.

Whether you are interested in a PING, TaylorMade, Titleist or Callaway irons, first learn a little about the new iron sets each company recently released. This will give you the confidence to know some of the clubs’ general specifications (specs) as well as the technological advances certain iron sets may have made in the passing years since you last purchased clubs.

You can trust these manufacturers to give you a brief summary of features and benefits for their new irons. Then try to be ahead of the game by having a favorite model of iron after you researched what might be best for you, like the popular and well-performing new PING i25 series, and you will be far ahead of the game.


By consultation, I mean pretty much demanding a proper education by your local golf store or club shop salesperson or pro on what type of iron will be best for you. There are so many types of irons out there that it can get overwhelming very quickly.

It’s important to be honest with yourself about your golf abilities, or it could spell disappointment or disaster on the course later for you. In reality, keep in mind that there are only a few decisions you have to make:

  • What iron head is best for you (traditional blade, midsize or game enhancement, oversize or game improvement)?
  • What type of shaft you prefer (steel or graphite)?
  • What improvements are you exactly looking for in this new iron set?
  • Do I want an iron that is more forgiving or more workable?
  • How much does the look and feel of the iron weigh in your decision?
  • What are the benefits of each iron head?

Answering these few questions can ultimately take hundreds of different irons sets down to just three or four. And you will quickly realize which iron sets could be best for you.


This phase of the buying process is the most important.  Here we can analyze and discuss what might be an iron set that is good and what might be an iron set that is great.

First thing to keep in mind before a fitting takes place, is whether the clubfitter that I am working with is both knowledgeable and certified. You will come away from this experience so much more confident and excited about your new irons if you are paired up with the right fitter.

During your personalized and custom club fitting, two main phases occur: deciding on the perfect set of irons; and fitting those irons to your ability and golf swing. When you are testing iron sets (or demo-ing them), keep in mind how they look and feel. These are the only two areas that a fitter can not analyze. The better the irons look and feel, the more confident the golf swing you will have.

These are criteria that must decisively match your needs.

Assess the assessor

Now performance is the deal breaker, of course. It does not matter how good an iron set looks or feels — if you aren’t hitting it well — you are not going to buy it.

At least I wouldn’t. So you don’t either. 

Now a proper fitting process will cover four main topics:

  • Static fitting (This determines what club length you need.).
  • Dynamic fitting (Tells you what lie angle you need.).
  • Ball-flight analysis (This will validate the decisions made to this point, such as iron head size and kind, club length, lie angle and shaft type.).
  • Course assessment (Get out and play! Make sure that the set is right for you and fit for you.)

Be aware of how the irons are performing. Do you notice any consistent ball-flight tendencies? If they are performing a certain way for you, are these good or bad tendencies?

Make your fitter aware of your progress after you leave the store. Fitting should be ongoing. Keep the lines of communication open. Don’t be afraid to keep asking questions after you’ve made your purchase.

It might take a couple of rounds or tweaks to dial them in perfectly. Remember it’s all about improving and having fun. The two usually go hand in hand but I promise if you spend the time and go through these important steps, both will occur.


Golf Club Components: Clubhead Topline

Golf Club Components: Clubhead Topline

The topline is the area on irons just above the face. It’s most pronounced at address. The thickness of the topline is widely considered a good indication of whether the club is designed for forgiveness or for workability, the latter of which is more popular with low-handicap players. The thickness is way for golf club engineers to place additional weight around the clubface perimeter, supposedly creating greater moment of inertia (MOI) or less twisting at impact with the ball for more centered shots.

The topline on TaylorMade's SpeedBlade Irons is one of the most pronounced in golf since it's about half the size of the sole on the bottom side.

The topline on TaylorMade’s Muscleback SpeedBlade Irons is one of the most pronounced in golf since it’s about half the size of the sole on the bottom side.

Clubhead Muscleback

Golf Club Components: Clubhead Muscleback

Golf Club Components: Clubhead Muscleback

An iron with the full back of the clubhead in place, unlike a cavity back. These are preferred by low-handicap players with the skill for more precision shots and better feel for the ball. Musclebacks are not known for being as forgiving, obviously, at least for the most part.

Clearly, Mizuno is not holding back on the iron it puts into its "dual" muscleback irons.

Clearly, Mizuno is not holding back on the iron it puts into its “dual” muscleback irons.