A Shaft's profile and how it compares to another.

[DeoreDX]

This may seem like a fairly open ended questio but...

 

Lets say you do a complete profile on Shaft A and a complete profile on Shaft B and they are within about 99% of each through the whole shaft. From the numbers could you expect the two shafts to play/feel nearly identically to each other?

[wildwilly911]

no, they could be built in complete different ways and still spec about the same

[MrParr1Noid]

This may seem like a fairly open ended questio but...

 

Lets say you do a complete profile on Shaft A and a complete profile on Shaft B and they are within about 99% of each through the whole shaft. From the numbers could you expect the two shafts to play/feel nearly identically to each other?

 

Wouldn't the shaft "profile" and shaft "specs" be two totally different things? If two shafts, regardless of how or what they were comprised of, had both the same "profile" wouldn't they play very similar in all ways, flex, bend point, and butt stiffness?

 

I don't really know the answer to this either, and it would be interesting to hear a professional view or two on this subject.

 

ty

 

 

no, they could be built in complete different ways and still spec about the same

[Johnny]

yes shaft profile and spec.. completely different...

 

I know what the OP is talking about.. poor man's ozik...

 

let us know.

[thewitt]

On the surface, one would think so.

 

If you add torque, weight and balance point into the equation, you get closer. You can still have different feel between the two shafts though.

 

Here's one way how - which I recently did through a shaft design of my own.

 

Torque in a golf shaft is measured by applying a twisting force to the tip of the shaft, and measuring how far the shaft deflects. It should be called torsional stiffnes, however it's called torque so we live with it.

 

If you design a shaft with a toque of 4 degrees and center the twisting properties in the middle of the shaft, that shaft plays completely differently than a shaft with 4 degree of torque having all of the twisting properties centered in the tip section.

 

The feel with these two shaft designs - all other specs being equal - is as different as night and day for certain swing types.

 

I don't believe we know enough today to measure the correct characteristics of a shaft for most players. Frequency profiles, balance point, weight and torque will get you close - however it will not get you all the way there.

 

Another variation that can cause real playing difference is shaft diameter. You can get the same frequency readings from two different shaft profiles by making the shaft walls thicker, making the shaft diameter larger, or laying fibers at a different angle to the mandrel. All of these techniques can modify the frequency profile of a shaft at a given location along the shaft so that the IE curves match - and they all resul in a different feel in the shaft during the swing.

 

-t

[JCAG]

When shaft profiling first started being talked about and some "semi" standards were discussed, many got very excited.

 

1. Some predicted that you would be able to "find" two shafts that were "identical" when they varied quite a bit in price.

 

2. Some predicted that you would be able to match a shaft no longer available.

 

3. Some predicted that a "datbase" could be built that would allow you to "plug" golfer "numbers" in and it would pick a shaft "best" for that golfer.

 

My experience with #1 and 2 is neither works well. My belief about #3 is that is was engineers and "spreadsheet" fitters doing that talking.

 

Many now believe that profiling is "just" another measurement that may not be as "all encompassing and/or as important" as it once was thought to be. Kind of like swingweight and frequency.

 

I believe there are to many "variables" (some not quantative like feel) to accomplish what many thought profiling would.

[Dyno]

When shaft profiling first started being talked about and some "semi" standards were discussed, many got very excited.

 

1. Some predicted that you would be able to "find" two shafts that were "identical" when they varied quite a bit in price.

 

2. Some predicted that you would be able to match a shaft no longer available.

 

3. Some predicted that a "datbase" could be built that would allow you to "plug" golfer "numbers" in and it would pick a shaft "best" for that golfer.

 

My experience with #1 and 2 is neither works well. My belief about #3 is that is was engineers and "spreadsheet" fitters doing that talking.

 

Many now believe that profiling is "just" another measurement that may not be as "all encompassing and/or as important" as it once was thought to be. Kind of like swingweight and frequency.

 

I believe there are to many "variables" (some not quantative like feel) to accomplish what many thought profiling would.

 

I agree with John and Tim. Profiling is useful but to an extent. Feel is such an important parameter but it cannot be adequately characterized by profiling alone. It's done by freq merely by default as most of us have access to the appropriate meters....but there's much more sophisticated methods being used by shaft designers....perhaps someone can shed some light on EI curves.

[thewitt]

It's more than EI Curves as well - they are simply more detailed flex descriptors.

 

I have two otherwise identical shafts of my own design that I'm attempting to fully characterize - working with a local university.

 

These shafts have identical EI curves, CPM profiles, balance point, total weight and torque.

 

The difference between the shafts is

 

#1 is sheet wrapped and has three distinct tapers in the shaft length (tip, middle, butt)

 

#2 is filament wound and is a constant taper shaft

 

Again, the EI curves are identical for these shafts - and both measure well within spec.

 

These shafts "feel" different as night and day. We're attempting to quantify these differences now to see if there is a way to more fully "profile" a golf shaft. It's likely to take some time to identify the elements that make these feel and play so differently. I suspect a new tool will be required as well.

 

It's very interesting stuff - but shows more about what we don't know that what we do know.

 

-t