There are many variables in a golf shaft. Some are designed and engineered by the manufacturer - stiffness, flex point, and weight. Other factors, however, become the province of aftermarket clubmakers and fitters who can adjust length, trim tips, and match frequency to suit your swing speed, tempo, and ball flight.
Over the last six or seven years, another way to tune shafts has emerged that proponents say best matches feel across a set, tightens shot dispersion patterns, and optimizes performance. Detractors, on the other hand, say it's unnecessary and expensive. Most manufacturers say their shafts don't need it.
Complicating the picture, it's a practice that goes by several names and actually can be performed in a number of ways. In this week's Bag Drop we'll try to shed some light on shaft spining, splining, and PUREing.
When I first brought up the idea of writing about shaft spining, my clubmaker urged me to avoid it, citing the fact that there is such a wide difference of opinion among clubmakers and shaft makers as to how it should be performed and if it's even necessary. But since he's done it to my last two sets or irons and I've seen and felt a remarkable difference, I decided to do a little research on my own. Here's what I found out:
The practice begins with the notion that no shaft, graphite or steel, is manufactured perfectly round or with a perfectly uniform wall thickness. The result is a hard spot running the length of the shaft called a spline or spine. By orienting the spline in a specific relationship to the head, the flex and performance of the shaft can be optimized.
It's the same process I and other custom fishing rod makers have used for years with fiberglass and graphite rods. You bend the rod blank and roll the butt across the floor. You feel a "bump" and that's your spline. This is then aligned opposite the guides.
Some early critics of this theory pointed out that unlike a fishing rod during a cast, the orientation of the spine in a golf shaft changes throughout the swing. Those who developed the technique, however, countered by showing with frequency analysis they could actually change shaft flex from stiff to soft depending on how they oriented the spine.
A Murky Rules History
Back in 1990, Robert Colbert, a Michigan welder, took a close look at his golf pro daughter's club shafts and found splines. After aligning them in a consistent fashion and seeing a remarkable improvement in feel and performance, he patented the process.
Immediately, the USGA issued a notice that this violated its rule on shafts and their bending and twisting properties. But soon after, embroiled in Ping square grooves litigation and afraid of another litigious front, they compromised and said only manufacturers could spine align shafts and only as long as they didn't advertise the fact.
This effectively put Colbert out of business and, because of the costs involved, kept spine alignment out of the game except for surreptitious clubmakers wise to the idea.
Years later, Richard Weiss, a wealthy Miami-based entrepreneur and late-in-life golf professional, purchased the rights and went on to convince the USGA that the process should be legal if it merely made the shafts consistent.
Thus, in 1999 the USGA ruled the process legal. Here's the USGA quote explaining the rule:
This Rule effectively restricts shafts from being designed to have asymmetric properties, so that however the club is assembled, or whichever way the shaft is orientated, it will make no difference to the performance of the club.
However, most graphite shafts have a small "spine" running along the length of the shaft which does make them bend a little differently depending on how they are fitted to the head. This is generally regarded as being "within manufacturing tolerances" (see preamble to Appendix II) and therefore not a breach of Appendix II, 2b. Manufacturers of clubs may orientate or align shafts which have spines for uniformity in assembling sets or in an effort to make the shafts perform as if they were perfectly symmetrical. However, a shaft which has been orientated for the purpose of influencing the performance of a club, e.g., to correct wayward shots, would be contrary to the intent of this Rule.
But, of course, there is still nothing to stop the unscrupulous from positioning splines to counter or promote hooks and slices… something the USGA has specifically ruled out. But really, how would anyone know? Seems like a pretty grey area to me.
Weiss went on to found SST, Inc. (Strategic Shaft Technologies) and call his method "PURE shaft alignment." Thus PUREing (Plane of Uniform Repeatability) is a proprietary process owned by SST and licensed to about 42 different clubmakers in 18 states here in the U.S. They also maintain a tour trailer to service pros on the PGA Tour.
Two of their licensees are notable: Hot Stix Golf based in Scottsdale, AZ has received much press lately on the success of their club fitting business and has begun to go national with a mobile tour. The other is GolfSmith which offers the service through their website.
Two shaft makers have bought into the process. UST offers it with some of their shafts. Royal Precision, at least until their recent acquisition by True Temper, made it available with their Rifle shafts. But other shaft makers like True Temper and Nippon have publicly said their shafts don't require the process.
What makes the PUREing process unique is the manner in which they identify the spine. Using a device with rollers hooked up to data-collecting sensors, they can provide a print out of the analysis. SST claims the process is accurate to within one degree. They also claim other methods can only identify the quadrant of the shaft where the spine exists.
Splining and Spining
Outside of SST's patented process, spine alignment has been practiced for years by hundreds of clubmakers across the country. Virtually every manufacturer's tour trailer offers the service to its contracted PGA Tour pros.
What differs among them is the manner in which the spine is identified and how the spine is positioned relative to the clubhead. Some use a frequency analyzer, some roll the shaft in some fashion, some use deflection boards. Some position the spine at 12 o'clock, some at 9, some even at 6. As my clubmaker warned, it's clear as mud. Which, I guess, makes it at least a brown art if not a black one.
Nonetheless, all methods seem pointed at helping the shaft arrive at a more consistent position at impact. Due to gravity (and other factors), a shaft bows down at impact. Aligning the spine the same way across a set helps with that consistency and can contain the downward deflection. It also helps achieve a more consistent degree of flex from club to club.
The overall process is pretty standard. The grip and clubhead are removed from the shaft. The spine is identified and marked and then the club is re-assembled with the spine in the proper orientation.
In the End…
Despite some shaft makers' protestations, spine alignment has become an accepted tuning method on all the professional tours and among a growing legion of amateurs who, like me, have experienced the benefits of the process.
That's it not more widespread probably has to do with cost. PUREing runs about $45 a club with independent clubmakers and fitters charging about the same.
The trick, it would seem, is to either go with SST's process or find and rely on a reputable, experienced clubmaker who knows what he's doing and can explain to you the method behind his particular madness.
If it's affordable for you and you are serious about your game and your equipment, spine alignment is definitely worth looking into.