Shaft U – Production Process 101
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Shaft U – Production Process 101

Shaft U – Production Process 101

Materials? Check. Tools? Check. Measurements, geometry, and all requisite industry know-how? Check, check, and check.

Now that we’ve covered the basics around what a shaft is and how it’s designed, we have to actually construct the darn thing. It’s a meticulous process which isn’t exactly a paint-by-numbers kind of thing.

To offer a food analogy, everyone knows someone with a recipe that’s often imitated but never duplicated. The secret isn’t in the recipe itself as much as it is knowing when to add a dash of this or dollop of that.

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Prototyping to Production

You’ve likely heard shaft companies talking about concentricity, which means the shaft is designed and produced in such a manner as to perform virtually identically regardless of installation orientation. Because you can’t bake quality control into a final product or simply increase the number of QC checkpoints, consistently high-quality products are the result of consistently high-quality materials, designs, and processes.

The philosophy is that you can’t inspect quality into a product; it has to be an inherent element of every step in a production process.

Quality of Materials

Top-end shaft manufacturers work to control the environment in which pre-preg materials are stored. In the case of Fujikura, it houses all materials (USA, Japan, Vietnam, and China) in large, commercial refrigerators at a constant 40˚F, 24 hours a day, 7 days a week. By maintaining this storage protocol, the relationship between the carbon fibers and resin is preserved. Because we’re dealing with what is essentially glue or plastic, it’s vital to ensure the resin does not change state until it’s ready to be cured around a mandrel – (a heating process we will get into later).

As mentioned in Materials 101, there are several select suppliers of raw materials which contract with major shaft companies to provide the necessary materials, based on desired tolerances and specifications. Some shaft manufacturers take it several steps further by applying a series of internal quality control measures.

Material Testing

In addition to keeping materials at a constant state, Fujikura utilizes a proprietary measurement system to make sure materials received are within desired tolerances. It routinely checks the specifications of the materials (tonnage, tensile strength, modulus, elongation, density, etc.) to ensure the nominal state of the materials hasn’t changed during a shaft’s lifecycle. These specifications are logged and entered into its design program.

An example of one of these checks is material weights or what’s referred to as Fiber Areal Weights (FAW). FAW is the weight of the fiber per unit area (e.g., a standard piece of polyester might weigh 1 oz/square foot). When dealing with composites were talking in grams per meter squared (g/m2), and the tolerance for such weights is far more precise.

The mechanics of it work like this. The supplier provides a FAW of the material before shipping. Upon receipt, the FAW is recorded and logged before the material into placed into inventory and stored in the refrigerator.

While FAW is a simple measurement, there are several additional specification checks and tests run on materials before they ever make it into the kitchen, let alone a final entrée. Two brief examples are tests for fiber uniformity (ensuring all fibers are flat/parallel and contain uniform resin content) and tonnage (measured by stretching a cured sample called a coupon until it breaks).

Because consistency is paramount, Fujikura performs the same series of tests on materials received at each of its factories in Asia as well as its prototyping lab in Carlsbad, CA.

Production Process

Once materials are selected and engineers have determined specific performance characteristics, a design sheet is printed, and materials are cut to precise specifications.

What is a design sheet?

A design sheet is a part recipe, part instruction manual. Every shaft company uses some version of one just like every home builder operates based on a series of blueprints. Fujikura’s design sheets are created through a proprietary shaft design program. These design sheets provide technicians with the materials (length and quantity) and the layout (how to cut the materials and what order to apply the materials to the mandrels). It seems like a relatively straightforward process, and while producing a shaft isn’t on the same level as brain surgery, it’s not microwave popcorn easy either.

Layout & Cut

Technicians follow the design sheet and use a large CNC machine to precisely cut materials. While there are different types of materials, the ply in which materials are cut and placed is most important. It’s why exceptional cake recipes suggest equal weights of sugar and flour and roughly equal weights of eggs and butter/shortening. Trust me on this one.

As shown in the design sheet, some plies run the full length of the shaft while others are rolled in a specific location to increase or decrease stiffness. There are also different material orientations that we’ve mentioned before.

Each orientation has a specific purpose and is listed below as a refresher from Materials 101.

  • 0 degree – fibers run along the length of the shaft (affects bending). Picture a hinge. The higher the stiffness of the 0-degree plies, the greater the resistance to bending during the swing.
  • 90 degree – fibers run perpendicular to the length of the shaft (provides hoop strength to prevent buckling and ovalization of the cross-section).
  • +/- 45 degree (referred to as Bias) – These materials lie across the 0-degree materials at +/- 45-degree angles (affects twisting). Bias plies are used to decrease/increase torque and help provide a smoother feel.

Once the design’s taper rate and parallel sections have been determined and materials have been cut into plies, it’s time to get rolling – shafts, that is.

Rolling & Mandrel

Technicians take the cut ply materials and hand roll them around a specially designed tool called a mandrel. Shaft companies often maintain a stock of mandrel designs that vary in size, shape, and contour. Having such a variety (Fujikura has hundreds) allows for each shaft to be rolled based on specific performance characteristics like weight, torque, and stiffness.

There are specific “clocking” locations labeled on the mandrel that correspond with the layout on the design sheet. These clocking locations specify when and where the materials are to be applied and serve to balance materials as they are rolled to ensure a uniform shape. This step is crucial but becomes even more so as the number of plies increases. Each additional ply increases the complexity of the process. For some shafts, the complexity of the hand-rolling is like preparing Baked Alaska, while for others, it’s more on the level of grilled cheese.

For reference, simpler designs may only use 5-7 plies, while more sophisticated and intricate designs can incorporate 20 plies in the development of a shaft.

Once the materials have been applied to the mandrel by hand, the mandrel and numerous ply materials are then placed on a rolling table which applies extreme pressure, fusing the materials around the mandrel. This is when the shaft begins to take shape.

Curing

Once the shaft is finished on the mandrel, Fujikura uses a special vacuum applied cellophane which removes air pockets and imperfections. The shaft is then cured inside the cellophane wrap in a specialized oven to ensure all of the air pockets have been forced out. More importantly, the curing process heats the resin in each of the materials (remember resin is glue), bringing the multiple layers of composites together to form one design (the shaft).  After the shaft is cured, the cellophane must be removed so paint and graphics can be applied.

The shaft is then sanded, washed, and dried to remove any imperfections. With Fujikura, every shaft design includes an outermost layer of carbon fiber, referred to as a sacrificial ply that is used to protect the design’s final layer of carbon fiber, and consequently, the integrity of the overall design.

Sanding down the sacrificial ply also allows the shaft to be prepped for paint and cosmetics. Before paint application, technicians recheck specifications (OD’s, handle and tip flex, torque, weight, etc.) to ensure every shaft is within target and on spec.

Paint & Finish

Shafts that have been approved and spec verified by technicians move into the final phase of production – paint and finish.

Shaft Cosmetics Add Weight

Once a 55g shaft is designed and produced, it still needs final cosmetics and branding. It may not be something many consider, but cosmetics add weight to a shaft, and the more paint applied, the heavier the shaft gets.

In general, lightweight paints are more expensive and shaft companies that delegate this step to an outside company often end up with heavier, more generic paints.

To minimize the impact of paint weight, Fujikura co-engineered with its paint supply partner what it calls Phantium® Finish; an ultra-lightweight paint that saves 5-7 grams (roughly 10% of the weight of the 55g shaft in our example) versus conventional paints. Weight which isn’t wasted on paint/cosmetics can be reapportioned into shaft materials. The effect of each layer of paint and the decal are accounted for in the design program and used in calculating the weight of the final design.

The shaft is then painted through a squeegee system and can require multiple layers of before heat transfer graphics or silkscreen cosmetics are applied.

With graphics complete, the shaft is now ready for final quality checks. The slightest difference between the initial design and the finished product can significantly alter the performance and durability. The same specifications are once again checked against the design sheet, and each shaft is checked for any cosmetic blemishes to ensure uniformity. Every shaft manufacturer has a tolerance range for each specification. The smaller the range, the tighter the tolerance, and the more consistent the final product. Plus or minus 2-3 gr for total weight is an excellent example of a tight tolerance.

What’s Next

Ready to eat? Not yet. Before this baby is ready to be plated and served, there are still a host of checkpoints and tests a shaft has to pass before it makes it out of the factory and into the hands of golfers, which is the topic for our next Shaft U chapter, Testing 101.

As always, please post your thoughts and questions below!

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Chris Nickel

Chris Nickel

Chris Nickel

Chris is a self-diagnosed equipment and golf junkie with a penchant for top-shelf ice cream. When he's not coaching the local high school team, he's probably on the range or trying to keep up with his wife and seven beautiful daughters. Chris is based out of Fort Collins, CO and his neighbors believe long brown boxes are simply part of his porch decor. "Isn't it funny? The truth just sounds different."

Chris Nickel

Chris Nickel

Chris Nickel

Chris Nickel

Chris Nickel

Chris Nickel

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Chris Nickel

Chris Nickel

Chris Nickel





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      Steph

      4 years ago

      Thanks for the interesting insights!
      Looking forward to your next article about FLOing, puring and spining, and hope that you actually perform unbiased testing with those techniques. They seems to be the black box of golf….

      Reply

      mondherius

      4 years ago

      All things considered; The manufacturing process is over 30 years old and way behind what’s being produced by aircraft composite companies, spar makers and the better known fishing rod companies out there… Not much either in design tools and quality control equipment. A little bit of a let down when you think about the size of this company and its commanding market share.. Oh well!

      Reply

      Chris Nickel

      4 years ago

      In all fairness, no company is going to provide access to proprietary software and give consumers full access to design tools, etc. It’s part of the challenge in covering topics such as golf shafts (you should have seen what we went through when we first asked a couple of ball companies about manufacturing costs…)

      Everyone wants answers, but very few want to talk. That said, 2020 should give us an opportunity to provide a bit more of an inside look at some topics and as always, if you have specific questions, please post them.

      Reply

      HDTVMAN

      4 years ago

      Amazing that there are no rules regarding shafts from the USGA and R&A. Their tolerances are strict on heads, but anything goes with shafts. As the club’s engine, this is the most difficult component to fit. Do you go light, medium, or heavy…low, medium, or higher spin…what length for driver-44″ to 46.75″…there are just so many variables. Just spin the wheel! Even when I was being fit for a driver at TPI, it’s trial & error & guesswork!

      Reply

      Chris Nickel

      4 years ago

      Check out pages 27-30 – https://www.usga.org/content/dam/usga/pdf/Equipment/Equipment%20Rules%20Final.pdf

      With that, while the “shaft is the engine” analogy is both inaccurate and overused, the more important element here is there are plenty of companies working to help golfers eliminate variables and better hone in what shaft specifications help that individual player to maximize a particular element of a fitting, be it distance, accuracy, trajectory, etc.

      Is a shaft fitting some parts trial, error and guesswork? Yes and no.
      Trial and error – certainly. But if you’re working with a “spin the wheel” fitter and it’s basically a roulette wheel operation, it’s time to find a different fitter as there are plenty of qualified options out there.

      Reply

      Dan

      4 years ago

      Very interesting article thanks

      Reply

      Rod_CCCGOLFUSA

      4 years ago

      Graphite shafts are not perfectly consistent. As a clubmaker, I order them by the dozen. The biggest variances are in stiffness and weak points along the length of the shaft. Each shaft has one (or even two) strong points or “spines” that must be properly aligned with the club head to keep it from wobbling of the swing plane. Have a club that never seems to return square to impact? Have your clubmaker pull it & check it out. Sorry, some are too bad to reseat successfully.

      Reply

      Chris Nickel

      4 years ago

      Not to get too far into the weeds on this one – and maybe it would be a great topic to have industry vets chime in on – but let’s start off with an important point of clarification.

      No graphite shaft is perfectly concentric 100% of the time. That said, there is a vast chasm between the most consistent/highest quality shaft companies and those at the opposite end of the spectrum.

      As such, any blanket statements around spines, weak points, variances in certain specs are generalizations that may or may not apply to whatever shaft brand someone happens to be thinking about at that time.

      Then there’s the whole conversation of spining/floing/PUREing which is dubious at best and at worst, an easy money-grab from clubmakers looking to make a couple of extra bucks off golfers who are none the wiser.

      Reply

      Bob Pegram

      4 years ago

      Checking which orientation causes a shaft to flex repeatedly in a straight line is quick and increases the likelihood of better shots. It requires only a vise to clamp the butt of the shaft and a way to temporarily connect the head to the tip of the shaft. It is assumed the shaft has been cut to length. Using a small piece of narrow rubber band between the shaft and head and wiggling the head on in the correct orientation is an easy way to do it, Just turn the head as you turn the shaft to test it. Keep the head facing correctly for accurate results.

      Steve

      4 years ago

      Way above me on this Chris but it was interesting to say the least. Kinda got the drift that Fujikura graphite shafts are the one of the best, if not the “best” shaft maker, in your eyes anyway.. I have always used Aldila graphite shafts, in fact, with every fitting I’ve had in the past, their shafts out performed all the rest. Would like your opinion of how Aldila stacks up to Fujikura in graphite shafts. Quality, performance, cost, etc..

      Reply

      Chris Nickel

      4 years ago

      When you look at market share on professional tours – which in this case is pretty valid given the absence of pay-for-play contracts – Mitsubishi and Fujikura are 1 and 1A depending on the week/year. Both are excellent companies and in late 2012 Aldila merged with Mitsubishi ( at that time in was Mitsubishi Rayon and is now Mitsubishi Chemical I believe) –

      With that, I’d say in a macro sense, Aldila stacks up relatively well and as always it’s going to come down to working with a qualified fitter who can find a shaft to match your individual needs.

      For me, I’ve found more consistent ball speeds with Fujikura’s Ventus Black (driver) and Blue ( 3 wood) but as always, your mileage might vary.

      Reply

      Artie

      4 years ago

      DO they still make high end shafts that wind the pre-preg fiber (not sheets) the way a fishing rod is spun from polymer infused fiber? Thx, Aryie

      Reply

      Bob Pegram

      4 years ago

      Artie – Paderson shafts are made that way.. Paderson used to make shafts for third party shaft wholesalers who sold them to custom clubmakers. I don’t know if they do that any more. I got lucky and have a set of those third party label Paderson shafts in my irons. They are extremely consistent.

      Reply

      T McKinnon

      4 years ago

      I agree with you Bob, I recently completed both a iron and driver fitting with Club Champion and the best shaft for both the driver and irons were the Paderson shafts. This was a surprise to me having tried several different shafts from different companies – thought I would be playing a Ventus shaft.

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