Need help understanding Flo true shaft read below please

[Stuart_G]

@GLF4EVR
1) FLO (and a freq meter) is used to find the spine and NBP (in fact that's the only reason to FLO) so there is no need to use any other method to find the spine of a shaft. Which also means there is no need to find the spine before you FLO. Or if you do have some other reliable way to find the spine, there is no need to FLO.
2) If you are using something else besides FLO to find the spine, chances are it's not accurate but I can't say that for sure since you didn't mention a specific method by which your spine finder works. But if it's a bearing based spine finder (sometimes called a "feel finder"), throw it out because they have been shown to be useless. Differential deflection (as opposed to total deflection) is another possible way to find the spine but a bit more complicated or involved than FLO.

[GLF4EVR]

Thanks for the response Stuart! You are one of the people on this site who's opinion I highly value. Right there with Howard. The spine finder is aircraft quality aluminum with high quality bearings. When I first got it I had a good level flat table that I used to use. Learned about this back in the 70's. The spine finder would always be correct with what I could find on the table. The table was lost in a fire years ago, so with the bearing feel finder I tend to check, check, & recheck my findings with it. Again it may be useless, but when I start on my FLO process the eventual "placement" is within a 10 degree total rotation in either direction. Even thought it might not be correct, thinking it at least gets me to the infield of the ballpark.

[Stuart_G]

It's not the quality of the device that's the source of the potential issues. It's the general methodology that is flawed. You might find this an interesting read: All About Spines

[Nard_S]

Thank you Howard. Thank you Stuart.

Good info that clears up some of my confusion. I can actually build a bearing based spine finder,(I'm a machinist), but it may not be worth effort so may just acquire a frequency machine and might doodle around with all this.

Question when one sets up to "weak side" does that mean weak is set at 12 o'clock or 9 o'clock in the hands. My guess right now is weak remains in vertical plane (12).

[GLF4EVR]

And thanks again on my end Stuart. Very good article. Have it saved for future use.

[Howard_Jones]

 

We might mark the shaft 12 o clock to align it with face angle, but the bending we talk is the shaft flexing against target line.

Since the weak vs strong is always about 90* apart, if we use the weak target line, the strong FLO line will be where we load the shaft on top of the swing.

 

 

[Nard_S]

Howard, thank you that is helpful'

 

[Stuart_G]

FYI - that link to the Tutelman site is just one (the third) of I believe 6 pages he has written on the subject (spines and alignment). Use the left and right arrows on the page or the links in "Article Contents" list on the left to navigate. I suggest you go through all the pages if you are interested in the subject.

There is even a page discussing different alignment options - https://www.tutelman.com/golf/shafts/allAboutSpines4.php

which is one of the more complex or foggy aspects of the topic in general. The short answer is that there are several beliefs (I'm not sure they even warrant the term 'theory'), there is no one clearly (or proven) 'best' way to align the shaft when asymmetry does exist. And it comes down to the fact that there is no one single axis that the shaft bends on during the swing. Here is one graph showing the axis the shaft bends on over time during a swing. And it can vary from player to player.

 

That's from another Tutelman article.

So what's more important? The axis of initial loading? The axis of max loading? Max force/acceleration? Some axis associated with some part of the unloading e.g. greatest deceleration or max kick velocity? Some axis before impact? Arguments can probably be made for any of them.

This shows similar graph from two other players (DL III and Greg Norman) - yes the article is a bit old but science really hasn't changed much. The modern GEARS set-ups might be able to come up with more insight but if anyone has looked into it, I haven't found any write-ups or data on the topic. Lessons from ShaftLab - 3

 

[Nard_S]

Thanks, great read Stuart. Article fleshes out the mature view both Howard and you have on the topic. There's a lot more on Tuttlenan I'm going to get to.

All this puts me more at ease with coming builds. I'm going to be using quality shafts so while I may delve into the FLO issue, I won't lose sleep over it and can put efforts in builds that fine tune fit.. May still acquire a a frequency machine, we'll see. The budget on all this is getting big, lol.