Hi DaveT Allow me to provide some background info. to the question:
Harry,
Thanks for the explanation. I was hesitant to answer the question as first posed because it sounded like a trick question, like there was some sort of "catch". Now that I fully understand the question, I know how to deal with it.
Earlier this year, I bought some of the new Apollo steel shafts. I found and marked N. Majority, not all were type 1 per bearing spinefinder. I understand in theory that all shafts are type 2 and not type 1 vs. type 2. I evaluated a dozen and they seemed pretty bad. Most rolled ok on a flat table, so not severely bent. Almost every shaft I tested had a severe wobbler on the N-S plane, to the point my GS freq. analyzer wanted to error out. I've never had the freq. analyzer error out from testing a steel shaft before ... why? Turned it 90 degrees and up to 6 cpm difference between N-S and 90 deg. rotation. These steel shafts resembled the graphite shaft demo that is a severe supershaft. Now I have another 'show and tell' shaft, to share with potential customers. Why wobble on N-S plane?
Why wobble on the N-S plane? Because we disagree on the definitions of N and S.
* Your definition of N and S is whatever your spine-finder tells you.
* My definition is the direction of minimum ("N") and maximum ("S") stiffness.
Those two need not be the same. And if you EVER find an "N-S plane" in your spine finder (that is, N and S separated by 180*), the two definitions are very different for that shaft.
John Kaufman and Charlie Badami have both done experiments, with different instruments, that show what the engineers on ShopTalk have been saying for years: all shafts are Type 2 if you measure the actual stiffness.
* John has measured a bunch of shafts using both a frequency meter (hey, he makes them for a living) and an "inverted flex board". Both showed that:
- Maximum stiffness occurs at 180* intervals, and corresponds to the plane of maximum frequency.
- Minimum stiffness occurs at 180* intervals (90* away from the maximum), and corresponds to the plane of minimum frequency.
* Charlie has taken a fair number of shafts that show up as Type 1 in a spine finder (he has three different bearing-based spine finders) and found the TRUE spine and NBP using a FlexMaster and a procedure we designed together. The true spine and NBP were not nearly the same as what the spine finder said. And, once he had found them by measuring actual stiffness, he did find FLO in the NBP and spine planes. But yes, they wobbled all over the place in the fake N-S plane that the spine finder found.
Hope this addresses your question. DaveT
