Variability in supposedly "identical" shafts

To get an idea of the actual flex of a shaft I take a golf club in my hands, one hand holding the shaft right next to the hosel, the other hand holding the shaft right next to the grip, thumbs underneath, and applying a certain force and observing how much the shaft bows. The difference between a regular and a stiff shaft is usually very evident, as the stiff flex bows less and presents more resistance than a regular flex. I know this is not a very scientific test but with a little practice it gives good approximate  and consistent results, at least in my experience.

Well, the other day I was at a local golf store and grabbed three "identical" Titleist 913 D2 drivers, 9.5 degrees and Diamana Blue 62 shaft in regular flex. I did my usual flex test and guess what, one of the three shafts was considerably stiffer than the other two. More like a "stiff" than a "regular". I repeated the test several times and there was no doubt one of the shafts was a lot stiffer even though all three were marked "regular".

When I got home I checked on a couple of Ping i20 drivers I own, both "identical" 9.5 degrees and "regular" flex. Again, one of the shafts was considerably stiffer than the other. I had noticed they played differently (one launched lower) but did not pay much attention to it and thought it was due to a loft variation in the heads.

I knew the actual loft of driver heads often varies by one degree or more in relation to what is stamped on the head, but now I see the shafts can also show a great variability in their flex.

Anyway, just wanted to share this experience.

As with all manufacturing processes, you cannot get identical shafts.

That is why pros try out many different shafts of "identical" specs to find one that works for them.