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”.

Graphite putter shafts, Part I: Why the big manufacturers with skin in the game are doing it wrong

I spend more time practicing putting (on the carpet in my office, which stimps at about 13, I figure) than any other part of my game, and I read with interest all the articles about putter design and the putting stroke that I come across. I also follow new developments in putter design, many of which turn out to be pointless, ridiculous, overhyped, or just plain wrong (see my review of the Stability Shaft by Breakthrough Golf Technology, on which more later in this column.)

In pursuit of better putting I have experimented with counterweighting by adding grip weights to my putters, for which there is a factual physical basis, unlike many of the spurious putting “innovations” which are touted in Golf Channel infomercials and even by big-name manufacturers. Extrapolating the concept of increasing stability by redistributing mass from the shaft to the ends of the club, the next thing that I wanted to do was to replace the steel shaft in my putter with a graphite shaft.

Changing from a steel putter shaft to a graphite shaft can save as much as 100 grams, freeing up that mass to be moved to the head and the grip end of the club while keeping the same total weight; a change which, as I explain in the counter-weighting article, increases the club’s stability in the long axis, which benefits speed control.

But before I talk about my putter-shaft experiment, let’s look at the current state of the art in graphite composite and multi-material putter shafts.

Who is making graphite putter shafts, and why?

There are three manufacturers that I know of that are currently marketing graphite-composite shafts, or shafts incorporating graphite-composite, for putters: Odyssey, with their Stroke Lab shafts (though not available as a retrofit item); Breakthrough Golf Technology (BGT) with their so-called Stability Shaft (retail cost $129.99 to $299.99); and LA Golf, which markets a line of graphite shafts up and down the bag, including three for putters (retail cost $419.00).

Of those three companies only Odyssey specifically cites the redistribution of mass as a benefit of the use of their graphite-composite shaft, and their Stroke Lab line of putters include the use of additional weights in the head and the grip of the club to redistribute the mass saved in the shaft. Both Breakthrough Golf Technology and LA Golf, however, cite the so-called “low-torque” characteristics of their shafts in preventing “head wobble” as the prime benefit.

These three manufacturers differ not only in the claims they make for the benefits of their composite shafts, but in the details of their construction. The Odyssey Stroke Lab shaft and the BGT Stability Shaft are multi-material units which combine a graphite-composite tube for the upper portion of the shaft with a length of conventional steel shafting for the lower portion which mates with the putter head. The Stroke Lab shaft uses unspecified means to bond the steel and graphite sections of their shaft together; the BGT design uses both an aluminum stiffener and a separate aluminum connector between the two sections.

The LA Golf putter shafts, on the other hand, are 100% graphite composite material, but like BGT, their advertising cites the “stiff, low torque” characteristics of their shafts in preventing head wobble or deflection that is “caused by traditional shafts” as the advantage of their product.

So let’s break it down:

Manufacturer            Construction Type                    Claimed Benefit

Odyssey                   Graphite upper/steel lower        Improved mass dist'n

Breakthrough Golf     Graphite upper/steel lower        Improved head

Technology                w/aluminum stiffeners and       stability

                                connector midshaft

LA Golf                     100% Graphite composite         Improved head

                                                                              stability

Both BGT and LA Golf claim that conventional steel putter shafts are weak—weak enough to twist in response to the forces exerted on them by the inertial forces resulting from the movement of the club acting on the mass of the club head.

The following quote is from the LA Golf website:

“Recent data shows that outside 12 feet, when a player begins forward motion the head wiggles slightly and that instability can change your putt line even if you read the line correctly and put the perfect stroke on it.

The head also wiggles when you strike the putt even fractionally off center (which everyone does) causing you to lose distance on the roll.”

It is, of course, utter nonsense to attribute the motions described in that quote to flex in the shaft; to do so is to reveal a complete lack of understanding of the magnitudes of the forces involved, and the ability of the structures being discussed to handle the forces to which they are subjected.

Of course, the people who want you to shell out anywhere from $130 to over $400 for a new putter shaft are counting on the average golfer taking their quasi-scientific marketing jargon at face value—but if you keep reading you will learn how they are leading you astray.

What do they mean when they say “torque”?

What the ad copy for golf club shafts refers to, incorrectly, as “torque”, is the torsional stiffness of the golf shaft. It’s measured by clamping the butt end end of the shaft in a fixed position and applying one foot-pound of torque—that is, a force of one pound acting at a distance of one foot from the center of the shaft—at a point further down the shaft and measuring how much the shaft twists. (The results obtained from this test can be greatly affected by the testing method—especially by the length of shaft between the clamping point and the point at which the force is applied—so comparisons between the data given by different manufacturers are not necessarily valid.)

This “torque” number can range from three or four degrees for a steel shaft to upwards of eight degrees for the more flexible graphite shafts—but these numbers are only really relevant for full-swing clubs: wedges, irons, hybrids, and woods; clubs in which the club face contacts the ball at speeds of up to 125 miles per hour (Note: PGA Tour pros average about 110 mph of club head speed with driver, and some go much higher.) Those high club head speeds produce very high resultant forces on the club head, and therefore, significant torsional forces in the club shaft.

For putters the force acting on the shaft, even as a result of impact with the ball, is orders of magnitude lower than for full-swing clubs, and the torque input to the shaft resulting from inertial forces acting on the club head before contact with the ball are so far below the threshold which would result in deformation of the shaft that they can be ignored.

The bottom line…

The claims that are being made by Breakthrough Golf Technology and LA Golf—that larger, heavier modern putter heads “overpower” a conventional steel shaft, and thus require their expensive, over-engineered offerings, which are actually no stiffer in torsion than a generic $9 steel putter shaft—are complete nonsense.

The all-graphite composite shafts from LA Golf are the right idea, but they appear to be doing the right thing for the wrong reason—and they cost waaay too much.

The sophisticated multi-component shafts such as the BGT unit and the Odyssey Stroke lab shaft introduce complexity where simplicity will do; the complexity adds no value, and actually compromises the potential effectiveness of lighter-weight graphite composite construction by the use of a steel lower shaft. The BGT Stability Shaft is the most egregious offender of the two, due to their use of two aluminum components mid-shaft, at the junction of the graphite and steel portions, which returns mass to the middle of the club.

In Part II of my look at graphite-composite putter shafts I will walk you through my home-workshop experiments, in which I modified my bargain-bin Tight Lies Anser-style putter as an experimental test bed.

Stay tuned.

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.