By Terry Koehler, The Wedge Guy

Terry Koehler has been in the golf industry for over 30 years and currently spends his days as the President of EIDOLON Golf, a small premium wedge company in Victoria, Texas. He's been blogging for over 3 years and has written hundreds of articles ranging from golf tips to equipment issues. His blog will appear on ClubSG twice per week. You can reach Terry to have your golf questions answered at askme@thewedgeguy.com.

Shaft Oscillation

One of the most amazing things to me is to see what a golf shaft will do when put under the speed, stresses and dynamics of a golf swing. Particularly with drivers. Last week I told you three stories where we helped local golfers improve their performance, simply by looking at their equipment. I promised more and so here we go.

When a customer comes in to our custom shop and wants to see if they can make improvements in their equipment, the first thing we do is create a chart of just what they have in their bag. From driver to wedges, we carefully measure lengths, lofts, lie angles and swingweights to get the static profile of the set. One of the most revealing measurements we get is when we put each club on the Digiflex frequency analyzer. That gives you a basic reading of the number of cycles per minute (CPM) the shaft vibrates when clamped and tweaked. From that, we can determine, generally, where the shaft falls in the way of flex.

Our goal in this analysis is to see the consistency from club to club in the golfers set in these key measurements that affect golf clubs’ performance. We can find disparity in lofts and lengths to figure out why distance gaps are not consistent. But the most revealing thing is what we find when we investigate the shafts. In most every golfer’s bag, even with “matched” clubs, we find shafts that are a half- to full flex stiffer or softer than the others . . . sometimes even more. And nearly every time that will turn out to be either the golfer’s favorite club or one that always gives them trouble.

Besides the frequency, however, one of the most interesting things you see when measuring golf clubs’ frequency is the oscillation pattern of the shaft. We clamp a small laser on the shaft that “draws” a pattern on the wall a couple of feet away when the shaft is going back and forth – kind of like the sparklers we played with as kids. You would think when the grip is clamped and the shaft tweaked, it would simple go back and forth in a straight line. Well, that rarely happens, particularly with graphite shafts. You see, shafts have a seam (steel) or spine (graphite) running the length of the shaft. And the placement of this seam or spine can make the club do all sorts of things when put under this motion. We see circles and ovals of all shapes and orientations, figure eights . . . and some wobble so wackily, they bang against the machine itself. It’s crazy.

But somewhere on each golf shaft (of reasonable quality that is) is a way that it can be oriented in the head so that it does draw a straight line. And that’s the way a good custom shop will build clubs – but it does not happen that way on the assembly lines in the major factories. You can buy the most top grade driver from the most reputable company, with a top name shaft and still get a driver that wobbles all over the place. And you won’t be able to hit it worth a lick.

Think of it like tires. Michelin and other top brands produce fabulous products, but you cannot just pick four off the rack, put them on your car and expect a great ride. They have to be balanced to that particular car and wheel. Sometimes it only takes an ounce or less to bring a 50 lb tire and wheel into perfect balance, so imagine what only a few grams can do to a 11 ounce driver? Shafts are a lot like tires. At 100 mph or more, that shaft is doing a lot in tandem with that head, and if it is not "balanced" perfectly to it, then it can go all over the place in the impact zone, making you think you’ve totally lost your game. It's not your fault!

One of my best golf buddies cracked the face of his driver (yes, he’s l-o-n-g) and got a replacement from the manufacturer – “just like it”. Well, the new one had a built in snap hook that he couldn’t control. I took it to the shop and found out the shaft was oscillating all over the place. We carefully pulled the shaft, identified the spine, reoriented it in the head, then put about 3 swingweight points of lead tape in the heel and he’s in business. Longer, higher and less “hook-y” than anything he’s ever played.

So, I might sound like a broken record, but a trip to a good clubfitter/builder can show you things about your equipment that you can’t imagine. And probably help you improve some things in your game that you thought were all you!

Share your stories about club tweaking if you have some, and go get one or two if you don't.


* The Wedge Guy's views and opinions are his own do not necessarily reflect those of SkyGolf.


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Terry Koehler is "The Wedge Guy" and President of SCOR Golf- The Short Game Company.

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