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YOO-HOO, guys. Yahoo is spelled with 2 "O"s.
Hi gingerjake,
Yup it is, but I have a lousy wireless keyboard that doesn't like to keep up with my typing skills, so it frequently drops keys that I don't punch hard enough. It's annoying and make me appear as though I can't spell very well. One day I'll change it.
 

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Hi GRIM,
I don't mean to be condescending in any way, but for what it's worth during those years I'm somewhat surprised you can remember much of anything at all. All things being what they were you had your hands full with taking care of your personal business, so I just assumed that much of the time spent on the forums was a diversion or mental break for you. If I was in your the same situation as you I'm doubtful if I would have been able to remember my own name!

I can't speak for what another man might be paying attention to in similar situations, but I myself wouldn't have the day to day presence of mind to stay on top of these small unimportant details. Some people write threads based upon reading and research they do. Other write based upon personal experiences they've had.

I write based on the more than 50 years of archery experience as both a competitive shooter and the many years of both working in an archery pro shop along with making my own arrows for almost 50 years. So it's from my head based upon what I've read and what I've learned over my lifetime.

I started very young at 12 or 13 years old shooting as youth in the NFAA. I stopped shooting competitively at age 53. I still shoot 8 months a year, but not in competition any longer. I shoot multiple times a week for my own enjoyment. Whether I decide to pick up my compound or my crossbow is only a matter of what mood I'm in and what I'd like to get done that day.

Xbow755

Actually, what I remember most, was the sincere compassion and the simple well wishing of myself and my wife. It was well and timely received.
It will not be soon forgotten.


GRIM
 

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It is interesting to see how far things have come but most don't realize how far there is to go.
The golf industry has made some serious advancements in spine identification and aligniment. No their goals are different than ours but that doesn't mean we can't use some of the same tech.
The following video was produced in 2012, it is what I see instore for us as archers and I have made my own version of the following arrow shaft tester.


GRIM
It is specifically the golf industry where Jerry and I first got our introduction into dynamic frequency analysis on carbon tubes. It's also the place where he and I purchased the frequency analyzers that we both own.

They were and are a couple of years ahead of us in the knowledge. When people are willing to pay upward of $1,000 for a high quality, matched set of clubs it warrants the time spent to perform the frequency measurements. On a $100 set of carbon arrows it becomes much more difficult to justify. Especially in Jerry's case when it's a business.

As previously stated, once we've identified the static Stiff Side Plane we've now proven the Neutral Plane is always exactly 90 degree from this point. The dynamic Weak Side Plane or another words the place where the shaft will actual bend during dynamic flight is usually somewhere along the Neutral Plane. Optimal Spine Matching would be aligning the Dynamic Weak Side Plain, but this would be very time consuming and out of reach for most people. That said, Alignment of the Stiff Side Plain is the next closest thing as long as people understand that it means their shafts will not always all flex in the exact same manner, since their Weak Side Plains are not aligned in the exact same manner.

When using the dynamic frequency analyzer it's further complicated due to the fact that along with 1 degree rotational measurements having to be done, what would you guess it is that exists that you can place around the shaft of an arrow that's gong to tell you that any rotation of the shaft is in fact a 1 degree movement or how far you've gone versus how far you have remaining to go to complete a 360 degree rotation? Don't get me wrong, these things can be made, but they are not readily available over the counter for sale. It's really not conducive for the home arrow maker. Even the hydraulic clamping device we use for locking the arrow shaft in place to apply the weight that the frequency meter obtains the measurements from is a costly piece of equipment for a home do-it yourself set up.

Xbow755
 

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Actually, what I remember most, was the sincere compassion and the simple well wishing of myself and my wife. It was well and timely received.
It will not be soon forgotten.


GRIM
As I probably mentioned to you in the past, I'm a late stage 4 throat and base of tongue cancer survivor, so I understand what it's like to be in that type of a situation. I also have feelings for other people and hate to see good people suffer. When I offer my help to others, it's never been just an offer. It's something I mean and stand behind.

If there's even one thing that I can do that makes their life a little easier then why wouldn't I do it? My view is I could have very easily not been on this earth any longer had things gone a different way. As long as I am here, then I might as well make myself useful and help others who can use the help.

Sometimes it's just a simple referral to a better hospital or a different doctor, Sometimes it's giving others guidance in an area they know little about. And sometimes it's much more, but either way I was raised knowing how to lend a hand when it's needed.

On Sunday I was in our living room looking out the front picture window into the cul-de-sac we live on. I saw a young boy about 10 on his bicycle lying on the ground. He attempted multiple times to get up off the ground but couldn't. I was surprised that nobody had come to his aid or attempted to help him. With that I turned to my wife and told her I was headed out to help the kid. As I ran over to him I could see his foot was somehow caught on the bicycle and he had fallen. I told him not to move and to relax. As I got to him I noticed that his shoe lace had opened and wrapped itself very tightly around the shaft of the peddle several times so his sneaker was locked to the top of the peddle. He couldn't get near it from the position he had fallen in on the ground. I simply loosened the opposite shoe lace enough to get enough slack to lift the bicycle and slip his sneaker off. Then I helped him to his feet and unwound the shoe lace from the peddle. I then returned his sneaker to him and helped him home to make sure he was okay.

As I walked back to my house I was really annoyed that the neighbors were in their driveway the entire time this was taking place and nobody would even walk over to see what this kid was screaming about. I guess some of us are doer's and some of us are watchers. I guess I suffer from not knowing how to mind my own business! :)
 

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OK, all you super-tech heads, 'splain me this. Grim tells me to read Tutelman, "All About Spines". I did. Tutelman tells me that in a solid shaft the Neutral Plane is an undefined internal plane through the length of the shaft when the shaft is at rest with no residual bend. When the shaft is flexed, the Neutral Plane becomes defined as the internal position at which the tension forces of the outside of the bend are equal to the compression forces on the inside of the bend. So what happens when you flex a perfectly symmetrical tube? It has four sites of opposing forces instead of just two; outside bend tension; inside wall compression; inside wall tension and inside bend compression. Where does the Neutral Plane go? It must still have one, but no Natural Bending Position since it is equally stiff at all angles of flex.

Now give the tube a spine by making it asymmetrical. Some radial angle is going to be more stiff than all others except 180 degrees from the first. Since 0 and 180 degrees would be equally stiff, then 90 and 270 should be equally flexible and represent the Natural Bending Plane of the shaft. As I understand Tutelman, the Neutral Plane lies within the wall of the arrow and moves from the center of the wall in the direction to balance tension and compressive stresses. In an arrow this implies that there are two parallel Neutral Planes, one in each wall. I can't figure out how these Neutral Planes would affect arrow dynamic behavior. I'm listening, hard!:D:D
 

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It is possible to have a shaft with zero spine, no spine no neutral plane

Now it is also possible that we simply don't have sensitive enough equipment to test with but that is far more information than we need to fling arrows.

GRIM
 

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. So what happens when you flex a perfectly symmetrical tube? It has four sites of opposing forces instead of just two; outside bend tension; inside wall compression; inside wall tension and inside bend compression. Where does the Neutral Plane go? It must still have one, but no Natural Bending Position since it is equally stiff at all angles of flex.
It does not exist in the archery industry!
 
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It is possible to have a shaft with zero spine, no spine no neutral plane

Now it is also possible that we simply don't have sensitive enough equipment to test with but that is far more information than we need to fling arrows.

GRIM
As I understand Tutelman, any flexed shaft will have a neutral plane whether it has a measurable spine or not. The tension stresses on the outside of the bend must be balanced with the compressive stresses on the inside of the bend. The neutral plane appears to be the 2-dimensional distribution of all stress balance points within the shaft. The presence of spine (asymmetrical stiffness) moves the neutral plane toward the position of maximum stiffness away from the center of the shaft. What puzzles me is how neutral plane can be synonymous with natural bending plane in describing dynamic flight characteristics.
 

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The following video was produced in 2012, it is what I see instore for us as archers and I have made my own version of the following arrow shaft tester.
Grim... Thanks for the video on Pureing. One of the most significant revelations to me was the fact that a shaft can have multiple spines. I should not have had to be told that. Shows where I am on the learning curve.:eek:
 

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Grim... Thanks for the video on Pureing. One of the most significant revelations to me was the fact that a shaft can have multiple spines. I should not have had to be told that. Shows where I am on the learning curve.:eek:
Then you will probably also like the following video
At the 6:30 mark he starts to describe zone profiling, the precursor to using a frequency meter and may help in understanding where Jon.henry755 was discussing 1 degree increments in his testing. I think you will like the information.

GRIM
 

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Then you will probably also like the following video
At the 6:30 mark he starts to describe zone profiling, the precursor to using a frequency meter and may help in understanding where Jon.henry755 was discussing 1 degree increments in his testing. I think you will like the information.

GRIM
Indeed I do! It's beginning to sink in, I think.:D
 

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As I understand Tutelman, any flexed shaft will have a neutral plane whether it has a measurable spine or not. The tension stresses on the outside of the bend must be balanced with the compressive stresses on the inside of the bend. The neutral plane appears to be the 2-dimensional distribution of all stress balance points within the shaft. The presence of spine (asymmetrical stiffness) moves the neutral plane toward the position of maximum stiffness away from the center of the shaft. What puzzles me is how neutral plane can be synonymous with natural bending plane in describing dynamic flight characteristics.
There may be a definition discrepancy here because the neutral plane in definition is the point the arrow bends and the natural bend is typically the stiffest side of the shaft. Arrows do not flex along the natural bend they flex along the neutral plane
 
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There may be a definition discrepancy here because the neutral plane in definition is the point the arrow bends and the natural bend is typically the stiffest side of the shaft. Arrows do not flex along the natural bend they flex along the neutral plane
Hi Jerry,
As always you bring a great deal of wisdom and experience to the table, but I have to ask you to re-read and review that last comment you wrote because it's throwing me and probably everybody else for a loop. Your statement claims that the natural bend or flexing point for an arrow is the "Stiff Side Plain". This is completely off base and in opposition to everything we know to be true. Arrows do not flex on their Stiff Side Plain, they flex 90 degree's from the Stiff Side Plain along their Neutral Plain at the Weak Side.

Please clarify!
 

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Hi Jerry,
As always you bring a great deal of wisdom and experience to the table, but I have to ask you to re-read and review that last comment you wrote because it's throwing me and probably everybody else for a loop. Your statement claims that the natural bend or flexing point for an arrow is the "Stiff Side Plain". This is completely off base and in opposition to everything we know to be true. Arrows do not flex on their Stiff Side Plain, they flex 90 degree's from the Stiff Side Plain along their Neutral Plain at the Weak Side.

Please clarify!
The natural bend in an arrow as I interpret the phrase is not the dynamic neutral plane, arrows do not flex dynamically along the natural bend it flexes along the neutral plane

gingerjake stated What puzzles me is how neutral plane can be synonymous with natural bending plane in describing dynamic flight characteristics.

I took this to mean that the arrow bends dynamically along the natural bend of the arrow. Now as I said it may be a definition discrepancy, I could be misunderstanding what is meant by the phrase natural bending plane.

If "natural bending plane" and "neutral plane" are both names for the point an arrow flexes dynamically then I misunderstood

I believe in the KISS method, this is why I have never deviated from using two terms and two terms only when discussing indexing.

The stiff side and neutral plane, I try to never refer to the natural bend, natural bending plane, first dynamic bending plane which was recently created by another builder.

The subject of spine can be very difficult to understand, if you look at Tutelman research you can get so confused and bogged down by words and their meanings.

So I use spine, deflection, stiff side, neutral plane, static spine and dynamic spine, there is no need in my opinion to muddy water that is already about to dark to see through.
 

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Let me clarify something, I have never read the Tutelman document nor do I intend to ever read it. I was mentored by an engineer in the golf industry and a gentleman with a doctorate in physics.

I'm not saying I know everything I'm simply too busy and feel the knowledge I have been given by the two mentors is more than enough to build superior arrows

I understand the physics of dynamic spine and apply that knowledge everyday when building arrows

I was told once by an engineer in archery manufacturing that they need to keep one thing in mind when designing a product and that point is that products must be designed with the least knowledgeable person in mind

This is why I like to keep terms, words and phrases simply when it comes to arrows, physics and dynamic flight of an arrow.

As I said earlier there are guys calling the static weak side of a shaft the first dynamic bend, it is not

The static weak side of a shaft has nothing to do with the dynamic neutral plane

So if we statically test to identify the static stiff side we have also found the dynamic stiff plane

And if we understand the physics of dynamic flight then we know the neutral plane is 90 degrees on either side of the stiff plane.

If we want to take it a step further to improve the arrows we can spine match the arrows along the neutral plane

It works, it's been proven and varified countless times over the last 16 years
 

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Question for Jon Henry or Jerry I bought my Ram and Analyser back in 2012 and I kept all info you guys posted over the years but when watching the video one thing came to my head and I could not find the article I had so I need to pick your brain It stated that a shaft should be cut before spine testing , cutting a shaft as little as one and a half inches can change the index mark up to 3.5 degrees any feed back would be appreciated thanks John
 
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