Are you really getting a stiff shaft? Think again

[Chieflongtee]

The following was copied and pasted from a recent post from John Kaufman(technical golf club guru)
http://www.csfa.com/

I recently gave a talk to the
Southwest Region of the PGA in Phoenix on shaft measurements. I
talked about Flex, Zone Profiling, Torque and Spine measurements. BTW
nobody in the room had ever heard of zone profiling. The more I
thought about zoning the more I became convinced that the normal butt
frequency we all measure is close to useless. I showed them two
shafts, an SK Fiber Pure Energy Stiff flex shaft and an MFS 58+ Stiff
shaft. I'm not sure where I got the 58+ shaft. Is that the old
Apache Micro 58? Both had a butt frequency of exactly 258 cpm with a
205 tip weight. At the 11" zone point the PE measured 753 cpm while
the 58+ measured 973 cpm. These two shafts are different as night and
day yet they were both exactly the same flex, 258 cpm.

The 258 cpm reading is usually called the butt frequency because it
is measuring the stiffness of the butt. Unfortunately we hit the ball
with the tip end of the shaft. The tip weight is loading up the butt
end when we twang . The golf swing is loading up the tip as we try to
accelerate the head at the start of the downswing. We are feeling the
tip end flexing not he butt.

I ran a little experiment this morning. I took and old PC 50
filament wound shaft I had laying around and sacrificed it to the
"cause". The PC50 has a pretty thick wall at the tip. It had a butt
frequency of 260 cpm. I took ten butt measurements and they were all
260. I then measured the 11" zone frequency. It repeated at 864 cpm
every twang. I chucked it up in my lathe and thinned out about 8 or 9
inches of the tip by about .015". The butt frequency once again was
exactly 260 cpm however the 11" zone had dropped to 831 cpm. So I
guess butt frequency measurements are really butt frequency
measurements with little effect from the tip.

[Break68]

Very interesting article.
Thanks Chief.

[mpare]

I had not realized that frequency measurements were focused on the butt end of the shaft and not toward the tip. Very interesting.

[mpare]

Your original quote caused me to look for more information on this on the site. I found "the rest of the story", which I confess to being a bit confusing to me but interesting nonetheless. For those of you with a penchant for this kind of thing here is the rest of what this club maker had to say under the heading Butt Frequency vs. Tip Frequency in the Technical Notes:

"Butt Frequency vs Tip Frequency

TECH NOTE 31: A few years ago an article was written in Golfsmith's Clubmaker magazine regarding a club that Scott Verplank did not feel was matched to the rest of the set. While all the butt frequencies in the set were a perfect match they found the offending club had a different tip frequency than the rest of the set. Tip frequency means clamping the tip and twanging the butt. They searched through their semi- infinite supply of shafts and found a shaft that had both the right butt and tip frequency. Scott was very happy with the newly reshafted club.

This seems a bit over the top for most clubmakers. As a service to my customers I supply a set of tip collars for the Club Scout to measure tip frequencies. I think I've sold four in the last two or three years. Apparently most clubmakers feel as I do.

I did have an interesting experience along these lines recently. I have a driver with an Aldila 50/50 Longwood shaft in it that I really like. I was testing some SK Fiber shafts and decided to build an identical driver to my Aldila driver. The Aldila was 247 cpm D5 at 45". I assembled a 45" SK driver and it came out 249cpm with no tipping and D5, pretty close. When I went to test drive the two the SK felt very much weaker even though it was actually a hair stiffer. The SK has a long 7" parallel tip section whereas the Aldila had virtually none. I thought maybe it had something to do with this tip frequency business. There was a difference. I decide to check the butt and tip frequencies of a number (22) of different brands of shafts and see what I got. Most of these shafts were lent to me by Raven. My supply is rather limited.

I don't think there's much of a standard for measuring tip frequency so I sort of invented my own. I found a very neat and quick way to measure the two frequencies of a shaft. I used a Craftsman 200gram 3/8" chuck to measure butt frequency. With the chuck still firmly attached to the tip I then flipped it around and clamped the chuck in my Club Scout Clamping Unit with the upper V block removed. The torque screw clamped down on the center of the chuck. It held it very nicely. I had built a small 50-gram tip weight to attach to butt. I guess most people use a split grip as a butt weight. This seemed a bit crude so I build a tip weight by drilling a 5/8" hole in a piece of 1" hex stock and putting a set screw in it. At 50 grams the weight is only about an inch long. For consistency sake I attached it to the butt at 45". With this setup I could get both a butt and tip frequency reading a matter of seconds.

I didn't really know what to do with the data I generated on all these shafts. I decided to ratio the tip and butt frequencies and see what I got. The SK definitely had a lower ratio than the Aldila indicating it was a tip weak shaft. At least it's tip weak when it's untrimmed. The Aldila had a ratio of 1.00. The highest ratio shaft award went to the UST Pro Force at 1.016. I guess that shouldn't be a surprise. I only used this shaft a couple of times but it always seemed to me to be stiffer than board even though I thought I had the frequency (butt) just right.

[ I deleted the butt and tip frequency measurements that he took because they are not easily copied into this posting. You'll have to look at the original. M Pare]

What do these ratios mean to the clubmaker? I'm not sure but maybe the cpm you've chosen for a customer might be adjusted slightly depending on the brand of shaft you plan to use and its tip/butt ratio. At any rate I thought the technique to generate these ratios was pretty neat. I'd be curious what you folks think about this subject.

Some time after running these tests it occurred to me there is a problem with the data. You'll note in the table that the steel shafts appear to be rather tip weak. This is probably not the case. If you go back to Tech Note 1 you'll see the frequency is inversely proportional to the "effective" weight on the end of the shaft. Effective weight is the sum of the tip weight as well as a portion of the weight of the shaft itself. With only a 50 gram weight on the butt end of the shaft the weight of the shaft becomes very significant. The problem gets even worse. When you realize the shaft is being clamped at the tip the major weight of the shaft is out in the vicinity of the butt itself. For more on this subject see Tech Note 36 on Zone Measurements."

[jvincent]

If you really want to get lost, go over to shaftprofiles.com.

They have frequency profiles for a LOT of different clubs. It's a good resource if you are looking for a matching shaft to something you like or are trying to understand why you like one shaft over another.

[Chieflongtee]

[QUOTE=mpare;378053]Your original quote caused me to look for more information on this on the site. I found "the rest of the story", which I confess to being a bit confusing to me but interesting nonetheless. For those of you with a penchant for this kind of thing here is the rest of what this club maker had to say under the heading Butt Frequency vs. Tip Frequency in the Technical Notes:


Hi Michael. Let's see if I can ''unconfuse''

The method described above is not used too much anymore except for the Golfworks.
Anyway here is the new method.



Butt frequency is measured with the butt of the shaft clamped in a frequency meter as shown in the pic above.(Usually 5 inches) A tip weight or the actual head is attached to the tip end of the shaft. The shaft is then twanged and the meter shows up a reading in cpm(cyclces per minute) The higher the reading the stiffer the shaft. So you can measure 10 different shafts and the butt frequency can be the same yet they will play and feel different.
Now if you slide the 10 shafts down 10 inches or so you and twang them the readings from diffferent shafts may start to be different. So the method is to measure different locations until you get to 11 inches os so down the shaftt(close to the tip)
Some shafts in the tip section will yield very high readings while some others will yield much softer readings So basically but frequency means squat as 2 shafts may have the same butt frequency but one has a very stiff tip section while the other has a softer tip section. Needless to say but I will say it anyway the shaft with the stiffer tip section will launch the ball a lot lower and will feel boardy if you do not have the swing speed for it.
Hope this helps