Adventures in putter-building: Frankenstein III

If you have been following my posts here for long enough you will have read (I hope…) several columns on the subject of putting, from why putting is hard, to how counterweighting your putter can help you make more putts, and how a graphite putter shaft can help (but not for the reasons generally touted by the folks who sell them.)

Like most golfers with something of an equipment addiction I own several putters, and consistent with my education and experience as a mechanical design engineer, I like to tinker with them. The five putters which I actually play (I have two or three more which are essentially antiques, of value only as curiosities) have all been bent more upright (within USGA limits, of course), tweaked as to loft (I prefer minimal to slightly negative loft – here’s why) and counterweighted for better balance and therefore better speed control.

The most recent addition to my stable is a self-built putter based on a Ben Hogan Golf BHB-01 plumber’s neck blade putter head. I installed the shaft that came with my Odyssey Golf Tank Cruiser 1 putter—which was re-shafted, for a while, with an early version of the BGT Stability Shaft (about which more here)—and my preferred Odyssey White Hot pistol-style grip. I drilled out the threaded fitting in the butt end of the Odyssey shaft to allow me more options for counterweighting than just the 15- and 30-gram counterweights that came in the Odyssey’s weight kit, and opened up a hole in the end of the Odyssey grip to allow the fitting of one of the range of Super Stroke Counter Core counterweights (25-gram, 50-gram, or 75-gram). I also filed an alignment mark on the top line and filled it with white paint.

The Odyssey Tank Cruiser, meanwhile, had the BGT Stability Shaft replaced with a $15 standard steel shaft. To reduce toe hang I removed the weight from the toe port in the sole, replacing it with cork, and installed a 20-gram weight in the heel port. I installed an Odyssey White Hot pistol-style grip, and opened up the hole in the butt end to take a Super Stroke counterweight. 

While the Ben Hogan-based putter is a “bitsa” build—put together from “bits of this and bits of that”—the real Frankenstein’s monster in my putter stable is the continuously evolving build that started out as a $17 new-old-stock Tight Lies blade putter that I purchased online. This putter, in one of its several modified iterations, was the one that I had in my bag in May 2019 when I played Pebble Beach during the USGA’s media day for the U.S. Open. It was a day that had its ups and downs, but one in which I had a great round on the greens, with eleven two-putt greens, and four one-putts.

Aside from a bit of tweaking for lie and loft, the first big change for this putter was the installation of the stock Odyssey shaft (with the 30-gram counterweight) when my Odyssey Tank Cruiser was getting fitted with the BGT Stability Shaft. From there I went to a more radical change, cutting down and transplanting a graphite shaft into the Tight Lies head—the shaft, an Aldila 350, came from a donor club: the driver that was part of my first set of garage-sale used clubs. As I explain in my column about the benefits of a graphite putter shaft, removing mass from the middle of the length of the club increases stability and improves speed control; “Frankenstein”, as I have dubbed the Tight Lies putter, was my first test bed for the benefits of this concept.

This putter went through several subsequent iterations that involved increasing amounts of lead tape on the head, with corresponding increases in counterweighting, all intended to bring it up to the same overall mass and swing weight as the modified Odyssey Tank. Damage to the shaft that occurred during a bout of loft/lie adjustment spelled the end of that particular experiment, so I decided to take it a step further.

Enter the latest iteration of the Tight Lies putter, dubbed Frankenstein III. It now incorporates a brand new graphite shaft, this time a Mitsubishi Rayon KURO KAGE Black Parallel iron shaft, stiff flex, .370 tip, cut down to yield my preferred 35-inch total length. To make the installation of a butt-end counterweight cleaner I sacrificed a Super Stroke grip for the threaded fitting which takes the Counter Core family of weights. Previous grip modifications to accommodate a grip weight involved drilling a hole in the butt end of the grip to a size that allowed the threads on the counterweight to bite into the rubber of the grip; gluing in the plastic threaded fitting from a Super Stroke grip makes the installation a bit tidier.

Frankenstein III, in all its glory

Shiny-new stiff-flex graphite shaft

Logo partly covered by the grip
shows that the shaft has been cut down

To complete the build I installed a 75-gram Super Stroke Counter Core weight. With a head weight of 391.8 grams, a shaft weight of 56.2 grams (less than half the weight, and at $29.95 less than 1/6 the cost, of the BGT Stability shaft), a grip weight of 67.2 grams, and an actual 74.0 grams of counterweight (plus a smidge for grip tape and adhesive) yields an all-up weight of 592.2 grams, or about 1 lb 5 oz. Thanks to the lack of the added lead tape that had previously been wrapped around the shaft of the 75-gram counterweight, this is about 20 grams shy of the weight of the previous iteration, and that of the modified Odyssey Tank. Loft remains at -1º, and the lie angle is 1º shy of the USGA limit, at 79º.

The 75-gram counterweight installed
in my preferred Odyssey putter grip

The swing weight of “Frankenstein III” is E5, making it a touch more head-heavy than its previous iteration at E4, and considerably more so than the modified Odyssey Tank, at D4, and the Hogan BHB-01 build, at D0. The new build feels well-balanced, and I have found it to be consistent and controllable when practicing on my office carpet (which stimps at about 13–14); I can’t wait for our current bout of rainy weather to end so that I can go try it out on real greens.

Playing around with putters is considerably easier and less critical than building or rebuilding full-swing clubs; because of the lower forces experienced by a putter during use you don’t have to worry so much about whether you got the crucial head-to-shaft bond exactly right. Even if you don’t go so far as to re-shaft a putter, a little bit of tinkering with counterweights in the grip and lead tape on the head may surprise you with the benefits that are derived from improving the balance of your “flat stick”.

What’s true—and what’s not—about what alignment stripes do for your putting

Under the dual headings of “Marketing People Just Want To Sell You Stuff” and “Golf Equipment Writers Who Recycle Manufacturers’ Marketing BUMF”, a recent article by an experienced and well-respected golf writer (whose BA in English Lit probably doesn’t qualify him to evaluate the dynamics and physical attributes of golf equipment) is promulgating more marketing nonsense from people who sell golf balls:

https://golfweek.usatoday.com/2023/04/12/callaway-chrome-soft-360-triple-track-golf-balls/

Callaway’s update to their Triple Track alignment aid system,

Triple Track 360, features blue stripes that now go all the way around the ball.

The article at the link above, about the new and improved Callaway 360 Triple-Track system—which now features blue lines that go all the way around the ball (that is, 360º – get it?)—states the following:

“(T)he two blue lines […] wrap completely around the ball, making it easier for golfers to aim the ball […] and to see if a putt is struck with a square face. If the lines stay smooth as the putt rolls, a player knows [they] hit the putt correctly with the face square to the target line. If the lines wobble as the ball rolls, the face of the putter was either open or closed to the line when it struck the ball*.”

This kind of stuff makes me weep.

The Triple-Track system, with a single rather heavy red stripe flanked by a pair of thinner blue stripes, was originally presented as a revolutionary upgrade over a single line as a static alignment aid, a quality that is supposed to be due to an effect called Visual Hyper Acuity (see: How Triple Track Technology Can Change Your Game). The effectiveness of “VHA” is said to have been certified by Dr. Carl Bassi, the Director of Research at the University of Missouri – St Louis College of Optometry, and also by Ray Barrett, an “entrepreneur and avid golfer” (whoever he is, and for what that’s worth).

I can’t speak to the effectiveness of Triple Track markings in helping golfers achieve micrometer-level alignment accuracy—vision science is not one of my specialties—but I can speak to its effectiveness in helping golfers assess the quality of their strike: it has none.

It’s very simple, and readily apparent to anyone who is familiar with the dynamics of impact and rolling objects: striking the ball with an open or closed face does not make the ball wobble, but the stripes may appear to wobble —which may appear to the uninitiated that the ball itself is wobbling—unless they are perfectly aligned with both the face and the path.

Face angle relative to path determines the direction that the ball heads immediately upon coming off of the face; “wobble”, as shown by the stripes on the ball, indicates only that the stripes were not aligned with the path that the ball started rolling on. If the ball starts to wobble later in the roll, that’s an indication that it hit some inconsistency in the putting surface and was thrown off line—but neither of these things means that the ball is rolling inconsistently—“wobbling”—due to having been struck with an open or closed face.

To help you visualize how this works, imagine slicing a section through the ball along the stripe to make a disc. That disc is like a coin standing on edge—if you roll it and it rolls true you will only see the edge of the disc-shape as it rolls away, like the illustration on the left, below. However, if the stripe is tilted to the path of the ball, the disc-shape described by the stripe will sweep a wider path as the ball rolls, like the illustration on the right, below, presenting a visual “wobble” even though the ball is rolling true to the path.

The only way to know whether the ball was struck with a face that was square to the intended path is to observe the ball’s roll relative to the intended line. Because the ball always leaves the club face on a path that is perpendicular to the face, observing the roll to note whether or not the ball starts on the intended path will tell you if face and path were square.

Watching a stripe on the ball as it rolls will only tell you if the stripe was aligned to the path when the ball started rolling, and that is pretty useless information.

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* (italics mine)

Book Review: “The Science of Golf”, by Will Haskett ⭐️☆☆☆☆

On the surface, golf is a simple game. You hit the ball, you find the ball, you hit the ball again—repeating that sequence, each time with the (hopefully) appropriate clubs, until the ball has come to rest in the hole. You count the number of times you hit the ball and write that number down as your score; the lower that number is, the better your score is.

Sports broadcaster Will Haskett cards a double-bogey
with this effort to explain golf technology to the layman.

In practice, however, there are a multitude of physical factors that determine how efficiently—that is, in how many strokes—you accomplish the goal of getting the ball from the tee to the hole. This book, authored by a sports play-by-play announcer and host who plays golf but has little experience as a writer and no technical training or background, is an attempt to explain the technical aspects of the game of golf, in a number of different areas, for the layperson.

The problem with this approach is that filtering technical information through a non-technical person to explain it to non-technical readers inevitably results in a significant loss of fidelity. In my 40+ years as a mechanical engineer I have been called upon many times to explain technical concepts to non-technical audiences; I have even written about the importance of such communication, and how to go about it (Presenting Design Concepts: How Mechanical Engineers Can Sell Slam-Dunk Ideas), and I can say with some authority that the author of this book shows himself to not be up to the task.

The author gives a shout-out to his wife (a “leadership consultant” whom he says is the actual writer in the household) in the Acknowledgements, in which he cites her encouraging declaration: “Will, you’re a good writer”, but reader, he is not. And what’s worse, the book’s editor, whom the author thanks in the first paragraph of the Acknowledgements, is apparently similarly very bad at her job, too.

Take this little tidbit from Chapter 1, for example: “A golfer’s mission is to enact as much force on the golf ball to make it move.” Get past the incorrect verb, “enact”, and you still stumble over the incomplete comparison which is started by the phrase “as much”. As much as what? As much as possible? As much as the other guy?

That example is just a taste; the text of this book is rife with similar instances of poor sentence construction, poor word choice and just plain incorrect grammar, but citing more of them would just be depressing. How they were not caught and corrected by a (presumably) professional editor is beyond comprehension.

Now let’s talk about the technical content. Here is where the combination of commonly promulgated misinformation and the author’s own shortcomings makes itself known.

Again in the opening chapter, the author lists the type of data that is gathered by launch monitors, and includes “sidespin rate” among those data points. Talking about “sidespin” is a common mistake that many lay golfers, and even some golf instructors make. It is a physical impossibility which I mention in my article about the myth of spin in putting (Debunking the Myth of Sidespin in Putting) because a sphere can only spin about a single axis. There is no “backspin” and “sidespin”, there is only spin.

A ball that is struck with perfectly square contact; that is, with the face of the club absolutely perpendicular to the swing path, will have pure backspin (the top surface of the ball moving in the opposite direction to the direction of travel), and it is rotating about an axis, the spin axis, that is horizontal—perpendicular to the Earth’s gravitational force. In the real world, outside of the achievement of hypothetical pure contact, swing path and face angle combine to determine the amount by which the spin axis deviates from the horizontal, and in which direction. The tilt of the spin axis, in concert with the spin rate of the ball and with the factors of air density, ambient air movement (that is, wind speed & direction), the aerodynamic qualities of the ball itself, and ball speed, determines the direction & shape of the ball’s flight.

Spin rate in rpm & spin axis angle in degrees are two of the data points gathered by the $22,000 Trackman 4 launch monitor system which is found in fitting bays and rich guys’ man caves, and set up behind many pro players on the range at Tour events. It is valuable information in the quest to optimize the golf swing, though I find that comparing spin axis angle to the bank angle of the wings of an airplane in flight, as is done in Trackman’s own online teaching series (Spin Axis) and quoted in this book, is a grievous oversimplification of the mechanics of the situation.

Many of the things that I found fault with in this book cannot be laid at the feet of the author; again, as a non-technical person he relied on the often-faulty information he was being fed by people in the golf industry.

Take the chapter on putting, for instance – in fact, to paraphrase the old-time comedian Henny Youngman, “Take that chapter, please.” And throw it away, because much of the information presented there is egregiously incorrect. After opening with a nice bit of exposition on the subject of strokes-gained: putting (it would be difficult to mess up Mark Broadie’s excellent statistical-analysis work on the importance of getting close to the hole), the author relates how Justin Silverstein, the head women’s golf coach at the University of Southern California, found that teaching his players to focus on speed led to a tremendous improvement in their putting stats. (See my column on this subject – “Putting, Part IV – Harvey Penick Was Right”.)

After that strong start, however, the chapter goes downhill rapidly, with references to the need for positive loft on a putter to lift the ball out of the depression it creates in the putting surface (an old wives’ tale), putting “topspin” on the ball (which, incidentally, is geometrically impossible to do with – what? – positive loft, that’s what), and matching path to face angle to prevent the generation of “sidespin” (there’s that word again.) He even trots out that tired old warhorse “muscle memory” when talking about grooving a consistent putting stroke.

Suffice it to say that I had to close the book and look away a number of times before I finished reading the chapter on putting. (By the way, for a reasonable, and fact-based, look at the interaction between putter and ball, I refer the reader—with all due modesty—to my recent article “Why your putts skid, and what you can do about it” at Will o'the Glen on Golf.)

There are many, many more instances of poor writing and incorrect or just poorly presented technical information in the book, but I can’t list them all—it would be too painful for everyone involved.

To sum up: Will Haskett’s book The Science of Golf: The Math, Technology, and Data is generally rather poorly written (which is somewhat forgivable in a draft version), but that poor writing persisted into the published version because it is also quite poorly edited (which is not forgivable.) The author is a layman attempting to explain technical concepts—which he does not himself understand fully—to a non-technical audience, and he fails rather badly.

Bright spots: the chapter on agronomy and the advancements that have been made in the understanding of growing and maintaining turfgrass; also, the chapter on data and decisions—but as I mentioned above, it’s really hard to mess up Mark Broadie’s work in this area. 

Low points: the chapter on putting (as described above) and the chapter on clubs, with such pithy quotes as “In order to get the ball in the air, you’ve got to have spin” and “Anything that has less spin launches higher and, obviously, it’s going to carry further and roll further” (Both quotes, by the way, from that well-known scholar of physics and aerodynamics, Tiger Woods.)

I won’t even mention the chapter on “the mental game”.

I cannot, in good conscience, recommend this book to the reader who wants to learn, even at the lay-person’s level, about the technical factors that drive the game of golf. It is too poorly written and presented (did I mention the several illustrations and charts, all in difficult-to-read low-contrast grayscale?), and too full of either incorrect information or poorly presented information, to be of any real benefit.

Why your putts skid, and what you can do about it

As I wrote in my previous article, despite the nonsense that you see and read online, or may even get from a teacher in an in-person lesson, you are not missing putts because you are putting spin on the ball. What you are absolutely doing, however, is skidding the ball. In order to understand why the ball skids, and how you can minimize skid and have better control of your putts, we have to take a look at the forces that are acting on the ball when it is struck by the putter, and after.

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There are two main forces acting on a putted ball which determine how the ball moves: the impact force which the putter imposes on the ball (which becomes momentum once the ball leaves the club face) and the friction between the ball and the putting surface*. These two forces are opposing; that is, they act in opposite directions—but more importantly, they act at different points on the ball.

Because the contact between the club face and the ball when putting is so close to the equator, or midline, of the ball, the impact force is very closely aligned to the ball’s center of mass (sometimes referred to as the center of gravity, or CG), so the impact force (and after impact, momentum), acts at the center of the ball, while the friction force, as shown in the illustration below, acts at the periphery, or outer surface, of the ball.

Impact force or momentum, opposed by friction, causes the ball to roll

The force of impact, and then momentum, translates the ball, while the tangential friction, acting at the periphery of the ball much like a hand on the steering wheel of a car, turns the ball around its center, causing it to roll. If a ball were struck while sitting on a hypothetical frictionless surface, without the opposing force of friction acting at its periphery, the ball would simply slide, translating without rolling, so the friction between the ball and the putting surface is an important factor in the launch conditions of a putt.

If impact force or momentum is not opposed by friction the ball will translate without rolling.

It is effectively impossible to achieve instantaneous roll at contact except in a very short, very lightly struck putt—a tap-in, or a steep downhill putt. For a putt of any distance (depending, of course, upon the friction characteristics of the putting surface), where the force of the initial impact is greater than the frictional force between the ball and the surface, the ball skids, slipping on the putting surface until the torque imposed by friction increases the spin rate to match the translational speed of the ball. This happens on nearly every putt, to some extent, and to improve your putting performance you have to understand why it happens, and what you can do to minimize it.

The length of the skid phase depends upon several factors: the delivered loft of the putter face (that is, the vertical angle of the club face at impact with the ball: static loft + dynamic loft); how hard the ball is hit; and the amount of friction between the ball and the putting surface and between the club face and the ball.

The illustration below shows a putter with 2˚ of effective loft at the moment of contact with the ball. The angle of the face places the impact point approximately 30 thousandths of an inch below the equator, or horizontal midline, of the ball (that’s about 1/32 of an inch; you know, those divisions on your scale that you can just about make out without putting on your reading glasses? Or maybe that’s just me.) The red arrows in the illustration depict the impact force vector and its horizontal and vertical components.

The slight positive loft on the putter face tends to lift the ball at impact.

The vertical component of the impact force, though small, is important. Its presence means that the ball is being nudged upwards slightly by the impact of the club face. There are those who will tell you that this upward nudge is necessary to get the ball out of the slight depression it creates in the putting surface by its own weight (including the folks at Scotty Cameron, who cite in-house studies that they say confirm this. Color me skeptical.)

What that upward nudge will do is off-weight the ball slightly at the beginning of its movement—if not lift it entirely free of the surface momentarily. The effect of this reduction in the contact between the ball and the putting surface is a reduction in the frictional force which induces roll, and therefore an increase in initial skidding.

Because positive loft, even in amounts as small as the standard 3.0˚ to 3.5˚ found on most putters, places the point of impact below the ball’s equator, it also adds a small counter-spin rotational force component to the motion of the ball, which works against the friction-induced force that creates forward rotation. The combination of upward nudge and counter-rotational force contributes to the ball’s tendency to skid, and must be reduced to minimize skid and optimize launch conditions.

I wasn’t able to find any studies which examined skidding with regard to control—that is, staying on line, but it has been shown to be important to achieving consistent distance control.

There was an interesting study** done in 2014 by Jeremy Pope, Paul Wood, and Erik Henrikson, of Ping Golf in Phoenix, Arizona, and David James of Sheffield Hallam University, Sheffield, England, which primarily focused on the effect of skidding distance on distance control. Utilizing putters with loft angles of 5˚, 3˚, 1˚ and –1˚, this study found that the putter with –1˚ loft performed best in terms of minimizing skid distance and producing consistent total putting distance, on both natural and artificial turf surfaces. (Take that, Scotty Cameron.)

I did a quick survey of putter manufacturers as background for this article, and learned (as mentioned above) that the standard loft for off-the-rack putters is around 3.0˚ to 3.5˚, with customization available from some manufacturers of from +3˚ to -2˚ (note that none of these number yield the negative loft which performed best in the 2014 study.)

Setting aside variables like turf type, turf condition, moisture, mow height, etc., one thing that can be stated with certainty is that a too-high delivered loft will increase skid distance, and can even result in a ball that lifts off of the putting surface slightly as it leaves the club face, resulting in a bouncing motion. This is bad for both distance and direction control.

Some studies cited in the book The Science of the Perfect Swing, by Peter Dewhurst—a rather dense little volume that will test your math and physics knowledge, your patience, and your eyesight (8-point type? Really?)—claim results that showed that the skid phase of a putted ball is typically one-seventh of the total distance of the putt, regardless of the length of the putt. Honestly, I find that hard to believe, and I have to wonder at the test conditions and methods that led to such conclusions.

My own home-grown testing, on a firm industrial carpet surface that stimps at about 13 to 14 (at a guess), using my stable of four putters which are all bent to a loft of approximately –1˚, showed mostly pure skid for the first two to four inches from contact, as shown on slow-motion video, with full rolling contact occurring at between six and eight inches on eight-foot putts.

As is always the case in putting there are a number of variables that affect the results, and the friction characteristics of the artificial putting surface I practice on is certainly one of them, but scientific studies and my own on-course experience have convinced me of the effectiveness of a slight negative loft.

(No brag, just fact: At the media preview for the 2019 U.S. Open at Pebble Beach, I managed four one-putt greens and eleven two-putts† in near-U.S. Open conditions with my mongrelized Tight Lies Anser-clone putter, counter-weighted and bent to a –1˚ loft. )

If warranted by on-course conditions, such as a soft, slow putting surface due to mow height or moisture, it is always possible to increase dynamic loft by moving the ball forward in your stance, thus increasing delivered loft.

Because there’s such a thing as too much of a good thing, reducing loft too much, for example by using excessive forward shaft lean or moving the ball back in your stance, tends to cause the ball to bounce because it is being driven into the putting surface at contact. This is also an undesirable result, because it starts the ball on its path in an unstable mode.

The Bottom Line

Of the factors other than impact force that affect the launch condition of a putted ball—delivered loft and the friction conditions of the putting surface—the one that the golfer can control is delivered loft. Based on proven studies, and my own personal experience, the first step is to reduce the loft on your putter (you can experiment with it, but –1˚ is a good starting point) and you can make adjustments, as conditions warrant, by varying the placement of the ball with respect to the vertical arc of your swing.

I started this article series with the intention of discussing why, like crying in baseball, there is no spin in putting—and why that spinning ball video clip on Instagram was a pointless demonstration based on misconception and ignorance. The scope of the article grew as I wrote, and then it split into two, despite my having held back a great deal of detail that I could have included.

I hope that I have been able to educate the reader a bit about the realities of an important aspect of putting—how the ball transitions from a static position to forward roll—and also in how you can go about maximizing the roll quality of your putts for more consistent distance control. (The importance of speed—and therefore distance control—was the subject of another putting article that I wrote about four years ago. My how time flies.)

Maybe if I get ambitious at some point in the future, I will take on the subject of the break.

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* As I mentioned, briefly, in the previous article, gravity affects the ball when the putting surface is slanted, but that is a subject for another discussion.

** Jeremy Pope, David James, Paul Wood, and Erik Henrikson, The effect of skid distance on distance control in golf putting (The 2014 Conference of the International Sports Engineering Association)

† I see you counting on your fingers, and yes, that’s only fifteen greens. The other three holes, including my nemesis, #6, are better not spoken of.

Debunking the myth of spin in putting

A while back I saw an Instagram post which consisted of a short video clip of a bi-colored golf ball spinning, top-like, around its vertical axis, on an artificial putting surface—but not otherwise moving. The text accompanying the clip says, “This ball has side spin and yet it stays on the spot... but I thought side spin makes the ball go off line. 🙂”

The post, by a UK-based putting coach named James Jankowski, was obviously trying to make some sort of point, in an amusing way, about the movement of a putted ball, but the video clip was both pointless and useless from the standpoint of presenting useful information. “Why?”, you ask—well, the spinning motion couldn’t make the ball go off line because there was no “line”—the ball was not moving along the putting surface. Since the ball was just rotating in place about its vertical axis, the frictional and inertial forces generated by this motion were balanced and did not produce a resultant force that would displace the ball from its position.

A certain amount of back-and-forth discussion ensued when I commented on the pointlessness of the video and its accompanying narration; in this discussion there was talk of skidding and sidespin as the ball comes off of the club face—which was not mentioned or demonstrated by the original video clip—and an unfortunate descent into the ridiculous notion of “rifle spin”. I decided, then, that it was pointless to argue, or even attempt to discuss the complexities of the motion of a putted golf ball on Instagram, especially with a self-defined expert who has obviously had no education or training in the physics of objects in motion. What I decided to do, instead, was to take the matter long form, as it deserves, and write an article about it.

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Before we get into a discussion about the movement of a putted golf ball, there are some important terms which we must define: rotation, translation, rolling, spin, and skid.

The first three terms are very closely related. Roll occurs when the ball is moving across the surface, or translating, and frictional contact causes the ball to rotate about an axis that is parallel to that surface. When a ball is rolling the translational and circumferential speeds are equal; that is, the ball is moving across the surface with a one-to-one relationship of surface contact to forward motion. A rolling ball travels a distance equal to its circumference—about 5.28 inches—for every full turn.

A ball that is both rotating—with one-to-one contact with the surface—and translating, is rolling.

Spin, on the other hand, means that the circumferential speed is higher than the translational speed; there is slipping, rather than one-to-one contact at the point where the ball touches the putting surface. If a ball is spinning while in contact with a surface it travels a shorter distance along the surface than the length that the circumference of the ball has turned.

Skidding is the opposite of spinning; the translational ball speed is higher than the circumferential speed. When the ball is skidding it travels farther along the surface than the length that the circumference of the ball has turned.

In short:

• Roll – the ball rotates at the same speed at which it translates.
• Spin – the ball rotates faster than it translates.
• Skid – the ball translates faster than it rotates.

Be aware that many of the coaches and self-appointed “golf gurus” whose lessons you will find online use the term “spin” incorrectly when talking about putting. They refer to putting “topspin” on the ball—that is, hitting the ball such that the top of the ball is moving forward in the same direction in which the ball itself is moving. What they are referring to is roll, and as I will explain in the next article in this series, it is not an action by the golfer that induces the forward rotation that constitutes roll.

The truth is that referring to spin at all when talking about putting is misleading and incorrect. For spin to occur when a ball is putted, with the ball in contact with the putting surface, the tangential force applied to the ball by the club face—the force that would cause the ball to rotate—must be greater than the frictional force applied to the ball by the putting surface in the opposite direction. Even if the ball leaves the surface momentarily, whether because of a high-lofted putter or a poor stroke (with backwards shaft lean adding loft to the club face), the near-vertical attitude of the club face and the generally low force applied to the ball (compared to full-swing shots) will not produce spin; i.e., rotational speed that is higher than translational speed.

Think of an approach shot to the green with a well-hit wedge, then compare, in your mind, the club head speed of that shot, and the loft of the wedge, to the speed and loft of the putter—and consider that the approach shot is traveling through the air, and not dealing with the friction of the ball-to-turf interface.

Trust me, you are NOT spinning the ball when you putt.

Now that we have (hopefully) put the idea of spinning a putted ball behind us, let us now address the concept of “side spin”. While it is physically impossible to spin a putted ball, this term is also used to describe the movement of a ball hit through the air—but it is a misnomer.

The proponents of “side spin” would have you believe that the golf ball is simultaneously spinning backwards, about a horizontal axis, and either clockwise or counter-clockwise, about a vertical axis (like the spinning ball in the Instagram video.). The truth is that a sphere can only rotate about one axis. (If you don’t believe me, read up on Euler’s Rotation Theorem and argue with Leonhard about it – (https://en.wikipedia.org/wiki/Euler%27s_rotation_theorem.) The golf ball cannot simultaneously have back spin, which all balls hit with a lofted club have, to some extent, and “side spin”. Even if a way could be contrived to simultaneously induce spin in these two different modes, the inertial forces acting on the ball would resolve themselves into rotation about one axis that is neither purely horizontal nor purely vertical.

What has happened when an airborne ball does not have ideal, pure back spin (as in the case of that slinging banana hook that just took your Pro-V1 on a one-way trip to O-B Land) is that the characteristics of the contact between the club face and the ball—a combination of club head path and face angle relative to path—has produced spin about a single axis that is tilted with respect to the horizontal. When that happens, the Magnus Effect, an aerodynamic phenomenon that produces an imbalance in the forces acting on a ball in flight, will cause it to curve to the left or the right, depending upon the direction of the tilt of the rotational axis.

On the other hand, a ball that is in rolling contact with the putting surface is rotating about an axis that is parallel to that surface. It will react to the angle of tilt of that surface (the break), if any, by moving right or left, but that movement is not induced by spin; it is a combination of the effects of momentum and gravity that makes a rolling ball “take the break”. Depending upon the loft angle and the force of the strike when the putter contacts the ball, and the relative frictional characteristics of the club-to-ball and the ball-to-putting-surface interfaces, the ball will skid for some distance before settling into rolling contact, but that is not only not spin, it is the opposite of spin—it is skid.

Since I have already gone on for well over 1,000 words debunking spin in putting, I will break here so you can catch your breath before we move on to the next subject—and the real bugaboo of putting—skid.

Read greens like a pro with the help of a GolfLogix Green Book

If you have watched much, or any, golf on television in the last couple of years, you have probably seen the pros reach for their back pocket when they get to the green. What they are reaching for is a green book, the logical follow-on to the ubiquitous yardage books that pros and their caddies have consulted during their rounds for many years. Made possible by the development of laser mapping technology that has been used to read the putting surfaces of golf courses all over the world, these books depict the contours of the green with contour lines like a topographical map, and the slopes as colors, or with arrows indicating direction and relative speed, or sometimes both.

Until recently these handy references weren’t widely available, but now, thanks to companies like GolfLogix, the makers of a smartphone golf scoring app, every recreational golfer with a few bucks to spare can have green books for many of their favorite courses.

The GolfLogix folks have mapped the greens of 528 golf courses in California at last count, and as near as I can tell from a rough count of the list on their website (https://store.golflogix.com), they have produced books for about 85% of the courses in the Bay Area/Monterey Peninsula region, so the chances are good that they will have a book for whatever course you want to play.

I have always contended that the putting stroke is the least difficult skill to master in the game of golf; the problem is, determining the proper line to hit the ball on, and how hard to hit it, are the two most difficult skills to master in golf—which is why putting befuddles so many golfers.

Here is where, if I were a pitchman for this product, I would start the spiel about how the GolfLogix green book will transform your game, drop strokes off your score, and turn you into the golfing god you always knew that you could be—but I’m not, and I won’t. What I will say is that these books are a handy on-course guide, as well as a great teaching tool.

The GolfLogix green books include standard yardage book features—diagrams of each hole with yardages and features depicted—with two diagrams of each green: a heat map which depicts the area and severity of the slope of the green with colors ranging from white (dead flat) to red (steepest), and a slope map with arrows which show the direction, and by their length the severity, of the slope of the different areas of the green. A handy YouTube video on their website will get you up to speed on how to use all the features of the book.

Of course, reading the extent and severity of the slope is just the start. Grain, surface dampness, and the type of turf you’re rolling on are also significant factors—but knowing the slopes is a good start.

It may take you a few rounds to get the hang of correlating the slope markings on the heat maps and slope maps to the contours of the green that you see with the naked eye; but honestly, after you do you may find that you are reading the greens better than you were before you started using the book—and may just leave it in your pocket when you pull the putter from the bag. Whichever way you go—using the green book as a teaching tool to boost your green-reading skills, or as a regular on-course guide, your game is sure to benefit from the addition of this arrow to your golf-skills quiver.

Putting, Part IV: Harvey Penick was right…

Scrolling through my Twitter feed the other evening, I came across a tweet from the British golf magazine National Club Golfer (@NCGMagazine) with a video featuring golf coach Gary Nicol (@GaryNicol67) explaining how in putting pace determines line, and gives you options for how to deliver the ball to the hole.

Now, I have insisted in the past that pace and line are of equal importance, because they are co-dependent. There are multiple combinations of line and pace that will get the ball to the hole – a higher line requires a faster-moving ball (more pace), and a lower line requires a slower-moving ball (less pace) – but a change in one always requires a commensurate change in the other to get the same result.

But that’s where I was wrong – in thinking about “…the same result”  – because as I watched the video clip I realized that while my assertion is accurate, it is only true in a limited-case scenario; pace and line are of equal importance and precisely co-dependent only for getting the ball to the same position at the hole – like in the illustration below:

Slower pace (in blue) requires a higher line; faster pace (red) requires a lower line. Pace & line are directly related, and of equal importance – if you want to get the ball to the same target on the cup.

As Gary Nicol explained in the video clip, there is a usable target width at the hole that is essentially three balls wide, as shown in the next illustration. Recognizing this fact, you can give yourself a wider target line to aim at, essentially the full area shaded in green, instead of thinking that you have to hit a narrow, very specific line at just the precise speed. Keep reading and I’ll explain how this opens up your possibilities for making more putts.

The size differential between the hole and the ball allows a target area that is about three balls wide, giving the golfer a wider selection of line than they might think at first. Higher line still takes a slower pace, but learning to recognize the wider target area will help you make more putts.

Why pace rules in putting

I touched on this concept, a bit, in my June 23rd post, Putting is hard – but you already knew that, right?, in which I wrote:

“…(T)here is a minimum ball speed that will get the ball to the hole, and a range beyond the minimum within which the ball will go into the hole and not bounce or lip out.

To further complicate matters, this speed varies depending upon how close to center the ball is when it gets to the hole. A ball traveling at a speed which allows it to fall into the hole on a dead-center hit may lip out if it arrives at the hole off-center. The more off-center, the slower the ball must be moving when it encounters the edge of the hole.”

Right there you have the basis for pace having the edge over line in importance: There is a minimum ball speed which will get the ball to the hole (“Never up, never in” as the old saying goes) – and if the ball comes up short, it doesn’t matter if it was on the right line.

The real argument for stressing pace over line is right there in the second paragraph from my June 23 post: it is the fact that, on a given line, pace also determines whether the ball will actually drop once it gets to the hole. Even if the ball hits the hole dead-center, it can hop out if it is moving fast enough (≈ 5 feet per second or faster, by my calculations); that max-allowable pace drops off dramatically as the ball’s interception point with the edge of the hole moves off center and the dreaded “lip-out” comes into play.

So, from the minimum speed that gets the ball to the hole, to the maximum speed at which it will actually drop into the hole and stay, there is a range of speeds which you must keep the ball within if you want to make that putt. And for every speed increment within that range, there is a target window within which the ball will actually drop – and if you haven’t figured it out by now, the slower the ball is moving when it gets to the lip of the hole, the bigger that target window is.

Wait, there’s more…

I started looking at the dynamics of the interaction between a moving golf ball and the rim of the hole – as in how to avoid the dreaded lip-out – and I started getting dizzy before I had even finished listing all the variables, so let’s just go with the broad concepts, without getting mired down in the math: A ball that skims the edge of the hole, with the center of the ball just inside the apex of the rim, has to be moving pretty slowly to drop into the hole – but at that low speed it will drop into the hole from any point at which the center of the ball is inside the diameter of the hole. In other words, at the minimum speed that gets the ball to the hole, the target window is pretty much the full diameter of the hole – 4-1/4 inches.

Conversely, the faster the ball is going the narrower the window gets. A faster-moving ball’s greater momentum increases the likelihood of the ball lipping out or just plain skimming over the edge of the cup, because it passes over the free space beneath it before it has had time to fall the distance required to let it drop.

Bottom line: the slower the ball is going, the more options there are for the line that will allow the ball to drop – which means that pace rules over line when it comes to making putts.

Harvey was right

There is one caveat to this discussion. Since the putting green is a highly variable surface, with grain, and bumps, and small irregularities – not to mention the dimpled surface of the ball itself – the ball tends to wander and not hold its line if it is moving too slowly. 

“I like to see a putt slip into the hole like a mouse.”

  – Harvey Penick

This factor dictates a minimum speed – which puts me in mind of the putting maxim of Harvey Penick, the revered Austin, Texas golf pro who taught such greats as Tom Kite, and Ben Crenshaw, who was one of the greatest putters the game has ever seen. Harvey said, “I like to see a putt slip into the hole like a mouse.” Harvey knew what he was talking about.

There is another putting maxim which defines a reasonable upper threshold for ball speed on the green: Get the ball to the hole at such a speed that it will roll no more than 18 inches past the hole if it misses. There are two reasons why this is good advice: 1) that 18-inches-past speed is not so high that you will have squeezed yourself into a narrow target window; and 2) if you do miss the putt, you have a short comebacker.

Speed rules

So there you have it. Pace dictates line, and the lowest speed that gets the ball to the hole on a steady course gives you the best chance of making the putt. Practice hitting your putts with consistent speed, and when you are warming up on the practice green before a round, do some distance drills and get a feel for the speed of the greens you’re going to be playing on. It will pay dividends on the course that will show up on your scorecard.

Counterweighting: What it is, and how it will help you make more putts

Welcome to Part III of my totally unplanned three-part series on putting – counterweighting.

After the introduction to my review of the Stability Shaft turned into its own article on why putting is hard, and after spotlighting how counterweighting the putter I had rebuilt with that fancy new shaft helped bring back the feel I was accustomed to, I figured I owed it to my audience to expand on the advantages of counterweighting.

In this article I will explain, without, I hope, sounding too much like a science fair exhibitor, the physical effect that counterweighting your putter has on its performance, and why adding weight to the grip of your putter can help you make more putts.

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First, let’s talk about MOI

MOI, or moment of inertia, refers to an object’s resistance to rotation, and is a function of the distribution of mass. It is measured with respect to an axis of rotation, which is an imaginary line that passes through the object’s center of mass (commonly referred to as center of gravity, or CG.) The higher an object’s MOI, the greater the amount of force required to make it rotate; and the greater the force that is required to rotate an object, the more stable it is. As you can imagine, stability is a desirable trait in a putter.

MOI is a term that is bandied about quite a bit in connection with the design of putters, but it is usually spoken of in connection with the club head, not the entire club. The MOI of a putter’s club head is measured with respect to a vertical line through the club head’s CG. Move material away from the CG and the MOI goes up, reducing the club head’s tendency to twist around the vertical axis; that is, making it more stable.

Stability about the vertical axis is a good thing in a putter because it helps the face remain square to the swing path, which in turn helps to ensure that the ball comes off the club face in the intended direction. Putter designs have been taking advantage of this physical property ever since Karsten Solheim hit upon the idea of moving material to the heel and toe of a conventional blade putter, creating the ubiquitous Anser-style putter.

Coming to grips with moment of inertia

Stepping away from the putter’s club head, let’s look at the other end of the club – the grip. Putter grips typically range in weight from 50-55 grams to upwards of 124 grams – a fraction of the weight of the club head; the shaft connecting the two weighs, on average, about 110 grams or so.

In a hypothetical “typical putter” – thirty-five inches long, with a 350-gram Anser-style head, a shaft that weighs 110 grams, and a mid-range grip of about 60 grams – the total mass comes to 520 grams; a little over a pound. Nearly 70% of that mass is concentrated in the club head – the last inch of the total length of the putter – skewing the balance point, which is the CG of the full club, well down toward the head.

Add some weight at the opposite end of the club, in the grip, and the balance point moves closer to the grip – not by a lot, but it only takes a small amount to make a noticeable change in the way the club feels in your hands, especially in motion. But… while adding weight to the grip end of the club does affect the balance point, it is the effect on the club’s moment of inertia, its resistance to rotation about that balance point, that is the point.

It’s all about that mass – and where it’s at

Think of it this way: if you took a plain putter shaft and put the combined weight of the head and the grip of our hypothetical “typical putter” in the middle of the shaft, it would require little effort to rotate the shaft in a circle, like an airplane’s propeller, by holding it in the middle and rotating your wrist. Take that same mass (equivalent to about ten golf balls, by the way), divide it evenly in two and put the two masses at the ends of the shaft, like a barbell, and it would take much more effort to rotate that configuration – by my calculations, a bit over 10 times as much. 

Now think about what happens when mass is added to the grip end of a putter. With the mass more widely distributed toward the ends of the club, it has less tendency to rotate about the center of balance; it is more stable – like the “barbell” configuration in our example. Imagine hanging the “barbell” vertically by one end, and moving it through a putting stroke – with the mass so widely distributed to the ends of the shaft, the ends of the shaft move together, almost as one.

By spreading the main mass concentrations further apart along the length of the putter, increasing the moment of inertia, the putter moves more uniformly both backward and forward in the stroke, with less tendency for the grip to lead the club head. More stable, more consistent, motion means less lag, less head wobble, a more consistent strike in terms of both direction and speed – and as a result, better control of both line and pace.

When I transplanted the counterweighted shaft from my Odyssey Tank Cruiser into the club head of my bargain-bin Tight Lies putter, that 30-gram weight (plus a bit more for the threaded fitting in the end of the shaft) transformed a pretty good putter into a really good putter – more stable, and more consistent. Similarly, when I fitted the Stability Shaft in the re-shafted Odyssey putter with the 50-gram Super Stroke weight kit, I regained the smooth consistency that I had missed when the putter first came back with the new shaft. 

What’s the bottom line? Counterweighting works

The change in moment of inertia that is realized by adding 50 or even 30 grams of weight to the grip end of a putter makes a noticeable change in the feel of the putter in your hands – and has a positive effect on the level of control you have over the strike you put on the ball.

The result? Better control of ball speed, better control of direction – and all other things being equal, more putts made.

The Stability Shaft – how good for your game is a high-tech, multi-material putter shaft?

As I mentioned in my previous post – Putting is hard – but you already knew that, right? –  I bring years of experience as a mechanical engineer, and a naturally skeptical nature, to the task of reviewing and evaluating golf equipment. I am very critical of the performance claims that equipment manufacturers make for their latest design innovation, and I subject them to close scrutiny. Putters seem to be the worst offenders when it come to gibberish tech-speak, but many golfers still seem to eat it up.

Because of the difficulty of putting and the irrecoverable nature of poor performance on the greens, club manufacturers seem to be constantly introducing some new high-tech innovation that will help golfers improve their putting. Sometimes it’s a training aid, sometimes it’s a design tweak to the putter itself, but it seems as though there is always something new coming down the pike when it comes to putters.

The latest high-tech innovation to come to putters is the Stability Shaft, from Breakthrough Golf Technology, with the involvement of well-known golf club pioneer Barney Adams, the inventor of metal fairway “woods” – the original Tight Lies clubs. While I will admit that this is a fairly new approach – little has been done with putter shafts over the years – the needle of my skepticism meter started twitching as soon as I read the ad copy on their website.

Wait, it does what?

The four-part, multi-material Stability Shaft is made up of a carbon-fiber composite tube, which forms the grip end and most of the length of the shaft; an aluminum insert placed inside the carbon-fiber tube at its lower end to “reinforce flexural rigidity”; and a 7075 aluminum alloy connector which adapts the upper end of the shaft to the conventional stainless steel tube which mates with the putter head.

The main structure of the shaft is described as “Eight layers of high-modulus carbon fiber specifically layered, wrapped and widened, with a no-taper design to greatly reduce torque.” This statement makes little or no sense in terms of mechanical attributes of the structure, or the functional requirements of this portion of the putter shaft. The little loading, either in bending or in torque, that a putter shaft experiences is concentrated at the other end of the shaft, where it is joined to the putter head.

Regarding the aluminum insert, their ad copy says, “Through finite element analysis a light-weight, 22-gram aluminum insert was developed and precisely located to reinforce flexural rigidity.” (“Flexural rigidity” is an oxymoron, by the way.) If the high-tech “high-modulus carbon-fiber” main body of the shaft is so precisely designed to resist deformation due to torque loading (which is what they really mean by “…a no-taper design to greatly reduce torque”), why are they adding half the weight of a golf ball near the middle of the shaft to increase rigidity?

Another claim for the Stability Shaft is that it “…delivers the face squarer at impact for improved accuracy and solid feel…”. The forces acting on a putter are low at impact, even lower during the swing. The rigidity and stability of a putter shaft is concerned with forces that are substantially less than those encountered in a full swing club, so what forces do the designers of this shaft feel are acting to deform the shaft of a putter during the swing? The only rotation experienced by the putter face will be the result of rotation of the entire club, caused by variability in the player’s grip, and arm and hand movement.

Fancy data says what?

The website for Breakthrough Golf Technology offers a pair of graphs which are said to show the velocity of the heel and toe of a putter with a standard steel shaft and with the Stability Shaft. Represented as showing toe and heel velocity at a data rate of 2,500 frames per second, based on the “Frame Number” scale along the bottom of the graph, they depict a little over 1/10th of a second in the motion of the putter, about 3/4ths of which is before impact. The lines for toe and heel are fairly uniform preceding impact (though apparently offset, which must be for clarity, to differentiate between the two, because unless the putter is moving through an arc, they should be moving at the same rate), but after impact the graph for a “Standard Steel Shaft” shows significant deviation of the two lines from each other, represented as a difference in velocity between the heel and toe. The graph for the putter with the Stability Shaft shows much more uniform velocities for the heel and toe, ramping up again evenly after the expected drop at impact.

Putter with a standard steel shaft

Putter with the Stability Shaft

Leaving aside the other questions which these graphs raise (the unlabeled velocity scale, for example, and the lack of information about how the data was gathered), what value is there in uniform velocity between heel and toe, if indeed that is what is actually being depicted, AFTER impact? If the ball is no longer in contact with the club face, no movement that the club face undergoes has any effect on the motion of the ball.

The amount of time represented in the graphs after impact, again, based on the frame number scale along the bottom, is approximately 4/100ths of a second. The changes in velocity depicted on the graph – which are not quantified – occur in a very short timeframe, and there is no information offered as to the magnitude of the displacement which these “velocity changes” represent. If the concern is the squareness of the club face, it is obvious that the relative displacement, therefore the relative positions, of the heel and toe of the club would be of concern.

You keep using that word. I do not think it means what you think it means

The more I looked at and thought about the data that these graphs are supposed to represent, the more I came to be convinced that these graphs must depict vibration in the club head measured at the heel and toe ends, not the velocity of the heel and toe of the club head.

The graph for the steel shaft before impact shows tight, consistent data for the heel and toe, with after-impact data that is consistent with undamped vibration in a rigid material, such as a high-strength stainless steel shaft. The graph for the Stability Shaft depicts slightly less-regular behavior before impact compared to the steel shaft data, and a well-damped behavior afterwards. The latter is consistent with a system which contains a vibration-damping component such as a wound carbon-fiber tube.

How I evaluated the Stability Shaft

My experience with the Stability Shaft is based on the conversion of my Odyssey Tank Cruiser blade putter. Before sending it off to the people at Breakthrough Golf Technology, I swapped out the counterweighted original shaft (because I would not be getting it back) for the plain steel shaft from (ironically…) an old Tight Lies stainless steel blade putter. The Tight Lies received the counter-weighted shaft from the Odyssey.

Needless to say, when I got the Odyssey back with the Stability Shaft installed, it felt much different. Not bad, necessarily, but different. The balance was off, for instance, without the counterweight, and I noticed that the head was a bit wobbly in the take-away as a result. In order to make this as complete a test I could, after a few weeks of using the club as-is I decided to remedy that situation.

A trip to a local golf shop netted me a 50-gram counterweight kit for Super Stroke putter grips. Even though I don’t use that type of grip, I was able to install it securely in the grip end of the re-shafted Odyssey – and it transformed the putter’s performance.

Counter-weighting increases the inertial moment of the putter (its resistance to rotation) along the long axis from grip to club head, stabilizing the club during the takeaway and the down swing (such as it is with a putter.) I had noticed the difference with the Odyssey when I first got it, installing the grip counterweight after having used the club for over a year with no weight in the grip, and I noticed it in the Odyssey Mk II (as I am referring to it) with the Stability Shaft. I now own two counter-weighted putters – the Odyssey Tank Cruiser with the Stability Shaft, and the old Tight Lies which inherited the Odyssey’s original shaft – and frankly, it has become a toss-up which one I put into the bag when I play.

In conclusion

Unlike the folks at BGT, I don’t have high-speed video, or sophisticated data-gathering equipment of any kind, at my disposal with which to evaluate clubs – only my eyes, ears, and hands. What they told me over a few weeks of using my re-shafted Odyssey putter is that the Stability Shaft is not a miracle solution to anyone’s putting woes, whatever they may be.

My knowledge and engineering experience told me that the claims that are made in their advertising copy are suspect, and the time I spent with the re-shafted putter showed that, at best, after becoming accustomed to the altered swing weight of the putter, I was no worse off than I had been before. Further modifying the club with the grip end counter-weight improved the swing stability of the “Odyssey Mk II” – which reinforces what I had previously learned about counter-weighting, but did not substantiate any of BGT’s claims.

So – if you have the spare cash to drop $200 on a putter shaft, and really want to explore the option, you may find that the Stability Shaft feels right in your hands, and with your swing; but if a putter with the Stability Shaft works better for you, it’s more about balance and feel that works with your particular stroke than it is about any of the performance claims that Barney Adams and the people at Breakthrough Golf Technology are making.