Shaft PUREING, Spining or Flat Line Oscillation (FLO)
Defining "Pure'd", Spined and FLO'd": Over the years, there has been plenty of discussion about golf shaft alignment and its potential as a game-improvement factor. As the topic evolved, three primary alignment methods emerged, Shaft PUREing, Spine Alignment, and Flat Line Oscillation (FLO) Alignment. Each of these techniques aims to identify the most stable orientation of a golf shaft so that it performs as consistently as possible during the swing.
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Shaft PUREing is a computerized process that locates the most stable bending plane of a shaft using proprietary analysis and measurement technology. Once this plane is identified, the shaft is installed so that it deflects and recovers in the most consistent manner possible during the swing.
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Spine Alignment is the earliest of the three methods and is a more manual approach. It involves identifying the shaft’s stiffest plane, the “spine", and positioning it in a specific orientation (usually facing or perpendicular to the target line) under the assumption that this alignment improves stability and accuracy.
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Flat Line Oscillation (FLO) Alignment serves the same purpose as PUREing but uses a more visual and the similar hands-on approach of Spine Alignment. In this method, the clubmaker attaches a laser tip weight, typically weighing about 205 grams to simulate the mass of a clubhead (see Figure 3), to the tip section of the shaft while the butt end is secured in a clamp. The shaft is then gently pulled and released, allowing it to oscillate freely.
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The clubmaker slowly rotates the shaft, repeating this process until the laser’s path forms a perfectly straight line, known as a flat line oscillation (see Figure 4). This flat-line "oscillation" indicates the shaft’s most stable bending plane, the orientation in which it deflects and recovers most consistently. Once this plane is found, the clubmaker marks it for precise alignment during club assembly.
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In most cases, FLO and PUREing will identify nearly identical planes of stability within the same shaft. Both methods are designed to locate the axis along which the shaft bends and returns most consistently to its original position. The main difference lies in how they determine that plane, FLO relies on a visual assessment of oscillation, while PUREing uses computerized sensors and algorithms to measure and record shaft behavior with greater precision. In practice, a properly executed FLO alignment often produces results that are functionally equivalent to those obtained through PUREing, though PUREing provides a documented, data-driven verification of the shaft’s orientation.
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It certainly seems to make perfect sense to align a golf shaft on the plane that produces the most consistent path to the ball during the downswing. Logically, you’d think the three prevalent alignment methods, PUREing, Spine Alignment, and FLO, would represent the most scientific way to achieve that goal, right?
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Well…not so fast my friend!
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Does Shaft Orientation Matter?: The premise behind these alignment techniques is that no golf shaft can be manufactured to be perfectly round or perfectly straight. Because of these unavoidable manufacturing tolerances, every shaft will have areas that are slightly stiffer or weaker than others. The belief is that by locating and positioning these areas correctly, the shaft can be oriented in a way that promotes a more stable and consistent path toward the target during the swing.
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In theory, that line of reasoning makes sense, but in practice, it doesn’t hold up nearly as well. As addressed in other areas of my shop notes, modern shaft manufacturing tolerances are far tighter than they were even twenty years ago. Today’s premium graphite and steel shafts are produced using advanced materials, automated layup techniques, and precision curing processes that virtually eliminate the extreme inconsistencies once common in earlier generations. The result is that most quality shafts now oscillate so uniformly that locating a single “best” orientation provides little to no measurable improvement in performance.
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I never really bought into any form of shaft alignment, well… to be entirely honest, at first I did. I invested in the laser setup and was absolutely gung-ho about aligning every client’s shaft to perfection. During testing, I noticed that in certain orientations, the shaft would wobble wildly—sometimes tracing almost a figure-eight pattern. As I slowly rotated the shaft through different positions, the amount of wobble would change until I finally found the flat line I was looking for.
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Success at last...or was it?
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It didn’t take long for me to notice something interesting during FLO testing. When I deflected a shaft and released it to begin oscillation, it always started by moving in a perfectly straight line, no matter how it was oriented in the clamp. In other words, only the way a shaft bends when initially released is important. During a golf "downswing" the initial bend occurs on a perfectly straight plane before the clubhead ever contacts the ball and the shaft begins to vibrate or oscillate.
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As satisfying as it was to find that perfect flat line, the real question was whether it made any difference in performance. After building and testing a number of clubs using various alignment positions, including what should have been the “ideal” PURED orientation, I quickly realized there was no consistent, measurable improvement in ball flight, accuracy, or feel. The data simply didn’t support the theory.
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What I discovered instead was that the shaft’s reaction during the swing was far more influenced by swing dynamics, loading patterns, and impact timing than by any subtle variation in shaft orientation. Even when installed several degrees off the identified PURED, Spine or FLO line, the difference in performance was undetectable. That experience taught me that while shaft alignment can be an interesting exercise in theory, in real-world club fitting and building, it’s a solution in search of a problem that today’s manufacturing tolerances have already solved.
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The bottom line is, Shaft PUREing isn’t cheap. It takes some pretty sophisticated computer equipment, and on top of the cost of the shaft itself, you’re looking at an extra $35 or more per club. Some clubmakers are true believers in the process, while others use it more as a marketing angle to bump up their fees. My take is simple, if a client really wants their shafts aligned, I’m happy to do it at no extra charge.
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At the end of the day, I’d rather devote my time and my clients’ money to the factors that truly influence performance, MOI or swingweight matching consistency, shaft profile selection, and proper fitting for tempo and release. These are the elements that directly affect how a golf club feels, loads, and delivers energy to the ball. Shaft alignment, in contrast, may look impressive under a laser, but in my experience, it offers no tangible benefit once the club is in motion. My goal has always been to focus on what actually makes golfers better, and that’s precision fitting based on science, not on theory.
Figure 1. SST Shaft Pure Machine
Figure 2. Golf Shaft Bearing Based Spine Finder
Figure 3. 205 Gram Laser Tip Weight
Figure 4. Successful "Flat Line'