EI = length of a segment 3 (cubed) X Load applied to shaft 48 Strain applied to load E refers to Young's Modulus which is the ratio of stress to strain. I refers to 'inertia'. Russ Ryden developed a machine that determines EI value with a 3 point bending test.
What is the EI profile of a golf shaft?
If you want to understand golf shafts the way a golf shaft engineer understands the, you need to see the three point EI profiles of the linear strength of the golf shaft. The term, EI is engineering short hand for E= Modulus of Elasticity and I = Area Moment of Inertia.
Do you rate golf shaft stiffness across brands?
The systems we have to rate golf shaft stiffness do not work across brands or even across models within brands. Most experienced club fitters use their experience to understand golf shaft stiffness. Many use some systematic method, most often frequency, to rate the shafts they work with.
Does shaft ovaling and overhanging weight affect ei measurement?
When questions about shaft ovaling and overhanging weight affecting the readings on my instrument arose, Dave studied the issue. He concluded in Errors in EI Measurement due to Shaft Weight that it was not a significant source of error because I applied a preload to the shaft.
What are the numbers on a golf shaft?
Brunswick shaft company patented a numbering system 4.0, 4.5, 5.0, 5.5, etc. The golfer was and still is confused about these numbers. The club making community made their own attempt at creating a standard. To date, the only standard is confusion. I began my journey to understand the golf shaft about 15 years ago.
How do you read an EI shaft chart?
0:252:31What is a Golf Shafts Bend Profile or EI Curve - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo how wide or how narrow that shaft is in the button inner tip section. And if you've seen ourMoreSo how wide or how narrow that shaft is in the button inner tip section. And if you've seen our steel shaft characteristics video you know that a wider diameter is going to always be stiffer.
What is an EI curve in a golf shaft?
An EI profile presents the local stiffness of a shaft, from one end to another. In most environments, more general terms are typically used such as stiffness, butt stiffness, and tip stiffness. These values represent an average stiffness of different regions of a shaft, or an overall average stiffness.
What do the numbers mean on my golf shaft?
These numbers are the weight of the shaft in grams. Shaft weights typically range between 50 grams and 85 grams with the 50-60 numbers being pretty common as seen in the example shafts above.
What does a 5.5 shaft flex mean?
StiffRegular – 5.0. Regular Plus – 5.5. Stiff – 6.0. Extra Stiff – 6.5. Extra Stiff Plus – 7.0.
What kick point should I use golf?
Unless you think you have a significant problem with a ball flight that is too low or too high, the mid-kick point golf club will be the best choice. The mid-kick point drivers are easiest to find in the game improvement category of golf clubs.
How do golf shafts compare?
Generally, the more flexible a shaft, the higher the ball flight. The lower the bend point in the shaft, the higher the ball flight (minor affect). Generally, the stiffer the shaft, the lower the ball flight. The higher the bend point, the lower the ball flight (minor affect).
What do numbers on Hzrdus shaft mean?
The Project X flex system uses numbers to denote flex. A scale of 5.0 to 7.0 is used to mark flexes between regular and Tour-extra-stiff. The HZRDUS Black comes in 60- and 70-gram weights with 5.5, 6.0, and 6.5 flexes, regular+, stiff, and extra-stiff respectively.
How do you know what shaft stiffness to use?
Take a look at the distance you hit your driver. This is a good, but very general, indicator. If you carry you driver 250 yards or more, go with Stiff; 230-250 yards, Regular; 200-230 yards, Senior; less than 200 yards, Ladies. Only the biggest of the big hitters is going to need Extra Stiff.
What flex shaft do I need for driver?
– Golf Shaft Flex ChartCarry DistanceSwing SpeedFlexUnder 200 yardsUnder 75 mphLadies or Senior200 to 240 yards75 to 95 mphRegular240 to 275 yards95 to 110 mphStiffOver 275 yardsOver 110 mphStiff or Extra StiffOct 15, 2019
Is a 6.0 shaft Stiff?
5.0 out of 5 stars 6.0 62g is VERY stiff! Great shaft! The only thing I would say to someone who is looking at this is if you normally play a stiff shaft you should go with the 5.5 62g variant. the 6.0 62g shaft is extra stiff in my opinion.
Who invented the rate of oscillation of a shaft?
Dr. Joe Braly introduced club makers to using the rate of oscillation of a shaft (frequency) to understand its stiffness. In the 80’s he did research on the PGA tour. He used a frequency instrument to measure the shafts used by the tour players. From this research, he developed a formula for the stiffness of ratio of the different irons in the set. The ratio he found was 4.3 CPM (cycles per minute) per one half inch of length of club.
Who owns Royal Precision shaft?
The Royal Precision shaft company was purchased by True Temper and with that purchase was the numeric stiffness rating patent. Here is a look at how that system is currently applied.
What is PCS in golf?
Inspired by the research done by the Braly’s, a club makers organization, the PCS, endorsed and taught frequency based club making to its many, many members. it was a time when shaft design was not as complex as it currently is and when frequency instruments were one of the few tools available to club makers for measuring shaft stiffness.
Is shaft frequency used in stiffness?
Shaft frequency is not of much use in evaluating shaft stiffness. The problem for club makers and fitters who recognized the importance of shaft profiling was that there was not an affordable EI instrument until I designed and manufactured one. They used the frequency instruments they had. As with all technologies, instruments and expertise evolves. Frequency profiling and frequency rating of shaft stiffness were an attempt by club builders to reverse engineer shaft knowledge not shared by the shaft companies. Affordable EI instruments have closed the knowledge gap between the shaft engineer and the club fitter.
Who first discussed shaft oscillation frequency?
The concept of using shaft oscillation frequency was discussed in the 1968 book, “Search for the Perfect Swing” by Alastair Cochran and John Stobbs. “Search for the Perfect Swing” is one of the first explorations of golf technology.
Is the area under the EI curve metric?
What you might have started to notice here is that Jeff Meyer’s system, area under the EI curve, as a single metric rating system , actually makes some sense.
Do golf shaft stiffness rates work across brands?
The systems we have to rate golf shaft stiffness do not work across brands or even across models within brands. Most experienced club fitters use their experience to understand golf shaft stiffness. Many use some systematic method, most often frequency, to rate the shafts they work with.
What is shaft testing?
When testing golf shafts, there are a number of tests that are used in the industry to assure the quality, characteristics, durability and performance of a golf shaft. Each shaft manufacturer and some equipment manufacturers have tests that each shaft must pass in order to be released for sale.
What tolerance is a shaft?
Many manufacturer’s do not share balance point information with the public but we test each shaft for balance point. Most shafts are within +/- .125″ tolerance.
How much does a 6M3 shaft weigh?
MATRIX’s published weight tolerances is +/- 3 grams. So a 6M3 could range from 60-66 grams and still pass the quality assurance test. Most aftermarket shafts are within this type of tolerance.
Is torque a standard?
Again, there really are no industry standards when it comes to calculating torque. We use a specific device from Kaufman Industries that relates a CPM measurement to torque. While it is a very consistent way for us to measure torque, our methodology gives torque ratings that are slightly higher than those published by the manufacturers. Most manufacturers have torque tolerances of +/- .2%.
What do the letters on a golf shaft mean?
Golf shafts are designated with a letter code, the letters most commonly being X, S, R, A, and L . What do these letters represent? Those letters tell golfers flex—the relative stiffness—of that shaft.
How to choose shaft flex?
These are just general guidelines, however; the best way to choose shaft flex is to go through a club fitting. Not every golfer can (or is willing) to do that, though.
What does it mean when a golfer's swing is slower?
The slower a golfer's swing, generally speaking, the more flex he or she requires in the shafts that are in their golf clubs. And the faster the swing, the more stiffness. Tempo also matters: A jerkier swing requires more stiffness, a smoother swing less stiffness, generally speaking.
Why do golf shafts bend?
Shaft makers vary the amount of stiffness because golfers have different types of swings—different swing speeds, different tempos—and different amounts of stiffness in a shaft better match up to those different swings.
What happens if you mismatch your golf shaft?
If your swing is mismatched to your golf shaft flex—if you are using an X flex shaft, for example, when you should be using an R flex shaft—you will have a harder time squaring the clubface at impact. The way your shots are flying can clue you into the possibility you might be using the wrong flex.
Why is senior flex represented by an A or M?
Why is senior flex represented by an A or M? " A" originally stood for "amateur." The "M" stands for "mature" or "medium." Also, of course, "S" is taken by "stiff."
When were steel shafts invented?
Alas, no. Golf industry veteran Tom Wishon, of Tom Wishon Golf Technologies, explains: "Shortly after steel shafts were introduced in the 1920s, steel shaft makers discovered they could change the diameter and wall thickness of the tubes to create shafts with different amounts of stiffness to better match to the different swing speeds ...
What is the kick point of a golf shaft?
KICK POINT: Modern shafts, particularly graphite shafts, can produce kick in different sections of the shaft — high kick, mid kick and low kick being three obvious points of reference. Fitters often spend considerable time matching a golfer’s swing with a particular kick.
How much does a shaft weigh?
WEIGHT:Overall shaft weight usually is expressed in grams. This reflects the weight of an uncut shaft. Once a shaft is trimmed, of course, the final weight is reduced. Stronger flexes generally weigh more than regular, senior or ladies flexes of the same model. True Temper’s Dynamic Gold, the most popular steel iron shaft on the PGA Tour, weighs abourt 130 grams. At the other end of the spectrum, Mitsubishi Rayon has a Bassara graphite driver shaft that weighs about 35 grams.
What is a golf shaft spine?
SPINE ALIGNMENT:Golf shafts, because they are round and hollow, have a spine that is a result of the manufacturing process. Spining (or “puring,” as it is called by SST Pure, which holds several patents in this technique) focuses on the alignment of a shaft in a clubhead: The spine is placed in a particular position in relationship to the head, the purpose being to produce optimal results. The effectiveness of spining for ordinary golfers remains somewhat controversial. Many touring pros, in the name of consistency and accuracy, have their clubs adjusted for spine placement. Most amateurs, however, do not.
How much does a true temper iron shaft weigh?
True Temper’s Dynamic Gold, the most popular steel iron shaft on the PGA Tour, weighs abourt 130 grams. At the other end of the spectrum, Mitsubishi Rayon has a Bassara graphite driver shaft that weighs about 35 grams. RAW: A raw shaft is an uncut shaft that has not been installed in a clubhead.
What is the most precise method of measuring shaft strength?
FREQUENCY:A more precise method of measuring shaft strength, although measurements from one frequency machine cannot necessarily be compared to those from another machine. As a shaft vibrates, these machines measure the number of vibrations. The higher the vibration count, the stiffer the shaft.
What is a raw shaft?
RAW: A raw shaft is an uncut shaft that has not been installed in a clubhead. BLANK: This is another word for a raw shaft. When clubmakers refer to a blank, they mean a raw shaft. SPINE ALIGNMENT: Golf shafts, because they are round and hollow, have a spine that is a result of the manufacturing process.
What does low torque mean on a golf swing?
Normal measurements are in the 2- to 6-degree range. A low torque number means less twisting of the shaft but also can mean a harsher feel . A high torque number is associated with a soft-feeling shaft, although there may be a sacrifice in accuracy. FLEX: The strength of a shaft as it bends during the swing.
