DAVE: I remember a long time ago doing some research on this and finding that Dunlop UK actually was the first to do frequency measurement in the late 1960s and frequency matching of shafts before Joe did it for Brunswick. While Dunlop's patent for what they did is long expired, I remember this pretty clearly from when I was doing research for the shaft book I did back in 1991. Joe was the one who really made it more of a household word in the game from his work on his own for his Precision Shaft Co out of Kennett Square, PA in the early 70s before Brunswick bought his company and brought him along to work for Brunswick.
TOM -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Dave Tutelman Sent: Friday, August 25, 2006 11:44 AM To: ShopTalk@mail.msen.com Subject: Re: ShopTalk: Flatline vs frequency chart In the early 1970s, Joseph Braly was the chief scientist for Brunswick Shafts, which eventually became Royal Precision. He came up with the idea of frequency matching at that time, and ran a bunch of human-golfer tests to see what frequency really meant. The outcome of these tests was that different golfers perceived flex differently but, when the data was statistically processed, the best fit to a CONSTANT PERCEIVED FLEX was when the frequency was sloped. The slope Braly came up with was 8.6cpm per inch, with longer clubs wanting a lower frequency to be perceived as the same stiffness by the golfer. Since that time, Precisions and Rifles have been built to 8.6cpm per inch (or 4.3 cpm per club at a half-inch length spacing across the irons). The other major shaft manufacturers had trim schedules that supported similar slopes. I don't know what the PCS "system" is, and would be interested to know if it endorses some particular slope, either explicitly or implicitly. There have been quite a few golfer tests since Braly's original experiments, and they almost always seem to come up with a similar result. The slopes are between 7 and 11cpm per inch for all tests that I've seen save one. That one was done by Eric Cook, founder of the Canadian company Swing-Sync. What they sell is constant-frequency matching, and that is what Cook's reported tests showed. I tend to discount his results because: * Every other test I've seen comes up with a definitive, non-zero slope. * I've read a bit of the test protocols for Cook's experiment, and feel it was biased to show a constant frequency. * Over a 40-year career, I've been close enough to instances of "sponsored research" to be suspicious of any study funded by Company XYZ whose outcome supports the product of Company XYZ. Anyway, that's how we got to where we are today. DaveT At 08:04 AM 8/25/2006, André Cantin wrote: >I was in the Canadian GW store yesterday and had a good conversation with >one of the managers who took the Rifle training before they went belly up. >According to him a flat line(single frequency) set does not produce the same >flex across the set. In his opinion the short irons are softer in flex than >the long irons. Of course his statement is based on a frequency chart where >the same frequency at a shorter length yields a softer flex. He also >believes that a shortened club(leaving the tip as is) yields a softer flex >as you are cutting away in the stiffest part of the shaft(butt section) and >obviously just the opposite if you lengthen the club. I would like to know >your opinion as I have read in many books that by shortening a club you make >it stiffer. Swingweight is not part of the equation in this discussion. I >also have always thought a single frequency set yields the same flex across >the set Thanks. >André. -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.0.405 / Virus Database: 268.11.5/426 - Release Date: 8/23/2006
