# Proof that stiff spine is ok for compound target archery



## tmorelli (Jul 31, 2005)

While I consider my own testing to be at least "deliberate" it isn't "scientific". 

My synopsis....

Spine does matter to the extent it is "stiff enough" on most bows. 
Spine does matter to the extent you cannot clear nock travel from the bow. That's what flex does.... hides (absorbs) nock travel.

So, in every case I've had bows that I was able to manipulate to absolutely minimal nock travel, the stiffest arrows performed amazingly well for me. I have owned bows with nock travel issues I could'nt solve (or wasn't willing to battle) and in those cases, softer spined arrows performed better. The stiff arrows have been shaft-to-shaft (less culls) and batch-to-batch more consistent for me. So much so that my bow decisions are heavily influenced by their ability to shoot the stiff arrows.

My scientific opinion 

....ok, maybe it's just my experience.


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## Fury90flier (Jun 27, 2012)

The only issue is that with a super stiff spine is less forgiving of shooter induced guidance.

As you fire the bow, the arrow starts to flex--tip staying still--back end being brought closer to the front...the stiffer the arrow, the less flex....this much you know.

now take it a step further and understand what the difference is between stiff and weak--just amount of flex, right...sort of.

as the arrow flexes, there are two nodes, one at front and one in back- the flexing happens between them- (think sine wave). Now so long as those two points are in line with your string/target/sight, you'll hit the desired target. Various changes in grip, anchor, release etc can change how all this lines up--spine too.

think of spine the way you do a shock absorber....sometimes you may want a stiff hug the road ride, sometimes you may want a more plush (softer) ride. This softer (weaker) ride is less subject to bumps in the road....same on a weaker spine. 

with a stiff spine- you'll have to be more "on" since there is less "cushining"...that spine will react faster to say, torquing of the grip.


BTW- this is not the right form for this thread- Ask that a moderator place this in the "general" section.


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## jaydub (May 16, 2008)

Sorry if it isn't the correct forum. Im sure it will get moved. I will with hold my reasoning for putting it here. accordingly. If an arrow flexes between nodes by design, how is a perfect paper tear possible at all distances? I cant get past that.


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## seafaris (Jul 29, 2012)

I don't understand why this isn't the proper forum. I think it's a good question that would be answered by some very good shooters. I know it has been answered before, but I would like to see some opinions especially if any one would be more of a proponent of more properly skinned arrows. I do agree with Tony, and he does a lot of testing, but he also has "what I would consider" perfect form. What about those who don't, or at least it's not 100% consistent?


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## Fury90flier (Jun 27, 2012)

You do not get perfect tears at all distances. you can get what looks like a perfect tear, but at different distance that tear will change slightly.

even bullets, you will not get a perfect hole at all distances....it's a trajectory thing. 

As the projectile travels it changes its relative approach angle- this will change the hole in the paper...unless it's a laser, all projectiles will travel in some type of arc. Combine that with the flexing the arrow does...you get tears.


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## Fury90flier (Jun 27, 2012)

seafaris said:


> *I don't understand why this isn't the proper forum.* I think it's a good question that would be answered by some very good shooters. I know it has been answered before, but I would like to see some opinions especially if any one would be more of a proponent of more properly skinned arrows. I do agree with Tony, and he does a lot of testing, but he also has "what I would consider" perfect form. What about those who don't, or at least it's not 100% consistent?


because it's basic in nature...information you will already know when you get to a more advanced level of archery....that puts it in the general archery section.

News flash- Tony DOES NOT have perfect form...he is consistent with his form---there is no such thing as "perfect" form, other than consistent. Not attacking, just letting you know to limit future frustration.


what you're asking in testing- would not have much relevance to the advanced shooters...it's common knowledge.

it's these questions, by the way, is why I thought of a "nuts & bolts/newbie competitive archery" thread...


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## N7709K (Dec 17, 2008)

Nodes aren't as much of a concern with carbons- they react different. Stiff will score better but misses are farther out; that said starting with a statically stiff shaft and building it to be slightly dynamically stiff will give the best results. 

You also need to know how your rig tunes dynamically and tune accordingly- I can run a very stiff arrow and outshoot "optimal" shafts with slight changes to rest position and cam lean


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## bigHUN (Feb 5, 2006)

Yes , you can shoot a stiff arrow, but ....
You CAN NOT score well FITA with stiff or with weak arrows, mentioning FITA as example where you have multiple distances and you know the exact POI where you want that arrow to hit....
30-50-70-90 meters if you want to score high you better do a homework, to spine match your bow and arrows, lets call the process ... :set1_thinking: bareshaft planning.
And all starts from the decision that "I want to have the peek weight 58.8 lbs and holding weight 23.4 lbs". Then the homework starts from that moment.....and lasts all the way until you happy with the result.....the end result shall be 1.5" group size on 70 in example, or wherever you put the expectations. And yes, I can group a dozen @ 70 into a 1.5" circle ...with my hootershooter!!!
Then the equipment is ready and we go playing games.


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## johnstde (May 24, 2012)

Newbie competitive would be great for me.


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## jaydub (May 16, 2008)

So big hun, if you went 2 sizes stiffer with your nanos and your hooter shooter, the group would not be the same @ 70 as the proper spine arrows? Not talking p.o.i but the group itself.


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## N7709K (Dec 17, 2008)

If discussing the high end of dynamic spine and relation to scores is basic then I'm in the wrong place...


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## cbrunson (Oct 25, 2010)

My general rule: Stiffer requires better tuning. For longer distances anyway. You can toss logs at 20 yds with anything and be ok.


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## jaydub (May 16, 2008)

cbrunson said:


> My general rule: Stiffer requires better tuning. For longer distances anyway. You can toss logs at 20 yds with anything and be ok.


This is opinion though. Im after fact.


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## sublauxation (Nov 21, 2013)

Unfortunately I think sometimes fact is hard to come by when there are so many variables, including bow and the shooter. I agree with Fury above though. Nobody has "perfect" form. Consistency is key.


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## cbrunson (Oct 25, 2010)

jaydub said:


> This is opinion though. Im after fact.


You could always do it the way the rest of us have, and test it yourself. It comes from testing different spines with different point weights, nock end weight, FOC, and tuning your own bow. You won’t find anything more than opinions based on experience unless you go buy software with spine calculators which are usually going to be conservative in favor of safety. 

The “FACTS”, or right answer for your set up may be completely different than other set ups. I have bows that shoot better with weaker spine and some prefer stiffer spines.


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## seafaris (Jul 29, 2012)

Maybe I used the wrong term with Tony, but his form is excellent and seems to be pretty darn consistant. I know that he shoots the fatter arrows to cut lines. As far as the rules go, I read it as Only topical productive conversation. 2. Target Archery questions or instructions only. I like this forum because the odds of getting a discussion going with the advanced guys is a lot better than in the general discussion forum. 




Fury90flier said:


> because it's basic in nature...information you will already know when you get to a more advanced level of archery....that puts it in the general archery section.
> 
> News flash- Tony DOES NOT have perfect form...he is consistent with his form---there is no such thing as "perfect" form, other than consistent. Not attacking, just letting you know to limit future frustration.
> 
> ...


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## jaydub (May 16, 2008)

cbrunson said:


> You could always do it the way the rest of us have, and test it yourself. It comes from testing different spines with different point weights, nock end weight, FOC, and tuning your own bow. You won’t find anything more than opinions based on experience unless you go buy software with spine calculators which are usually going to be conservative in favor of safety.
> 
> The “FACTS”, or right answer for your set up may be completely different than other set ups. I have bows that shoot better with weaker spine and some prefer stiffer spines.


I have tested for myself. I personally have better results across the board with "correct" spine arrows. I am open minded and I try to be honest with myself. I didnt want to be partial to my own findings if they were incorrect, thus the reason I asked if any scientific evidence was available, rather than opinion. F.y.i I am not a Newby. I have won many state and sectional venues, and been in the money at more than a couple national shoots. You were quick to dismiss my knowledge and ability, simply because im looking for an answer to something that is common knowledge. I know that it can work. I wanted to know why.


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## bigHUN (Feb 5, 2006)

jaydub said:


> So big hun, if you went 2 sizes stiffer with your nanos and your hooter shooter, the group would not be the same @ 70 as the proper spine arrows? Not talking p.o.i but the group itself.


yes, you can go 2 sizes "stiffer number" for the cost of longer carbon, instead of in example 28.4" carbon length you shall cut it ...I am saying this offhead now...30.6" to match the spine of your DW....almost right but most likely will cost you arms and legs. 
Why?
Last year I cut my CX nano XR 410's 0.750" shorter (based on SS 120g points) and the hootershooter could not group the dozen inside the size of the ten ring on 70 meters. Sent email to CX and I follow their direction....the price to correct the FOC was a set of tools steel points = $180 ..............now you do the math....
The same SS 100g points on my other set of CX nano XR 450's the same bow mounted to same hootershooter group the dozen inside the X ring !!!!
A 3/4" carbon shorter cost me extra $180 to correct the FOC.
These are my final arrows for FITA and Field competition:









This next season I will be shooting the CX nano pros in 400 spine, also a new bow.. to many unknown parameters...looking forward to a long tinkering...


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## cbrunson (Oct 25, 2010)

jaydub said:


> I have tested for myself. I personally have better results across the board with "correct" spine arrows. I am open minded and I try to be honest with myself. I didnt want to be partial to my own findings if they were incorrect, thus the reason I asked if any scientific evidence was available, rather than opinion. F.y.i I am not a Newby. I have won many state and sectional venues, and been in the money at more than a couple national shoots. You were quick to dismiss my knowledge and ability, simply because im looking for an answer to something that is common knowledge. I know that it can work. I wanted to know why.


I see. I would bet that most people have had similar results which if compiled and documented, could be considered evidence I suppose. Trouble is, I don't think many document their results.

I bet if you could measure nock travel accurately and change it consistently with a bare shaft, you could prove or disprove your theory.


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## jaydub (May 16, 2008)

cbrunson said:


> I see. I would bet that most people have had similar results which if compiled and documented, could be considered evidence I suppose. Trouble is, I don't think many document their results.
> 
> I bet if you could measure nock travel accurately and change it consistently with a bare shaft, you could prove or disprove your theory.


Now measuring nock travel, I admittedly know nothing about. im assuming my double shoot through bows have no horizontal travel, but cant say on vertical. I dont like to assume, so I will try and find out.


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## rohpenguins (Dec 2, 2012)

The article below helped me peice it all together, when I started playing around with different combinations of arrows, tips, length and fletching the principles outlined below seemed to hold true. There are so many variables to everyset up I wish there was a formula, that bow A set at X#, X DL will need a spine of XXX and an XXX tip with vanes that are XXX and set at XXX. Unfortunatly there is not and all we can do is lots of trial and error. Manufactures charts are a good start as are computer programs but there is always going to be a need to feild test. Thats where forums like this are invaluable I don't want to spend money on a set up that appears it will work out just to find out that the same set up has been tried and had poor results. We all are on the quest to find the most accurate set up coupled with the most forgiveness. I think what the OP is asking is appropriate for this forum and I hope all the information provided here helps him find the ultimate set up.


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## rohpenguins (Dec 2, 2012)

What is spine? 

"Spine" is the general term for specifying the stiffness of the arrow in terms of a matching draw-weight; the spine is derived from a measurement of the static deflection of a shaft of standard length when a standard weight (2 lb IMO standard, or 1 lb if GNAS standard) is suspended from the mid-point of that shaft. 

A specified matching spine value will not necessarily be the same as the actual draw-weight of the bow. 
There is commonly a difference between a perceived static spine value and what may prove to be the best dynamic spine match.

The spine match can vary from the 28" shaft length standard according to the length of the shaft, as well as by other modifying factors, such as point weight, pass width in the bow, brace height, string efficiency and shaft diameter.

Pass width is a pretty basic consideration that is too often ignored. Along with the brace height and to some degree the cross sectional shape of the pass it determines the lateral angle of the shaft in the bow, which in turn establishes the amount of paradox we are asking the arrow to recover from when it is shot from the bow.


What is the difference between stiffness and spine?

They are just different ways of describing the same thing.
It's probably easiest to think of "spine" as being the name for system of selecting and specifying shaft stiffness.

The older method of bending a shaft in the hand relies developing upon a feel for the "stiffness" of a shaft in the absence of an accepted standard of measurement and specification.

The static method of bending a shaft using a given weight can still be applied pragmatically in comparing the "spine" of one arrow against another of the same type and proportions which performs acceptably. 
Just drive a couple of nails into the wall and compare the deflection of the two shafts using the same weight, making sure that the grain orientation in the shafts is correct as you apply the weight at the shaft's mid-point.


Do we have to spine our arrows?

Sorting out the equipment has always been about choosing an arrow that shoots well out of the bow. 
We can observe how cleanly it shoots - which is not the same as observing how cleanly we can shoot it. 
Consequently it is useful to understand what we are making the arrow do, so as to be able to make useful decisions about factors of equipment selection and set-up which will determine where the arrow will go.

Do we have to measure spine? Perhaps not, but being able to select a shaft by assessing the static deflection of the shaft can make the process of shaft selection more predictable.

The oldest and most basic method is probably just the empirical process of making a lot of arrows, shooting them carefully and selecting the ones that we like best, based upon where they go.
By then developing a feel for the stiffness of these selected shafts, we can then select more carefully: for length, straightness and size (diameter) and then using our feel for the stiffness by bending the shafts in our hands.
Even so the ultimate proof is in a blind test (numbering and then not identifying each shaft before it is shot) of shooting so as to eliminate any personal bias in identifying those shafts which are consistently more widely dispersed.

We could then test the deflection of a shaft that flies well and measure its deflection before producing shafts that are a close match in deflection.
As long as this process is internally consistent, it will not matter if it is just a couple of nail in the wall, with a weight suspended upon the centre of the shaft and a pencil mark on the wall to mark the deflection.

In all many primitive bow cultures we will find dissimilar arrows being used for particular specialised tasks; even so it is still useful to be able to select shafts and to make up arrows of any single type that can produce sets which are more predictable in use, rather than using sets of any one type where the shafts in that set are are less predictable.

Before the current standardised method of measuring shaft deflection was worked out, until quite recent times the recognition of a close but not exact relationship between density and stiffness led to the selection of shafts by weight being the common method of shaft selection. 
When we read of the old lawn archery "five shillings and sixpenny" target arrow, it refers not to the cost, but to a weight equivalence for that shaft in a particular combination of coinage.
In this case being the equivalent of 7/8 oz or 383 grains, which is in the ballpark for a light target arrow in a bow of around 55 to 65 lbs.
This system is known from the written record to have been used by the Chinese fletchers of the bronze age.

Not until shaft flexing behaviour upon release had been observed photographically was a correlation established between the precise measurement of static deflection and the systematic matching of dynamic flexing to the draw-weight of a standard bow, which in turn lead to the creation of a tabulated system of spine measurement.

Our understanding of what happens to the shaft may be more complete, but the pragmatic method of shooting and observation remains unchanged.
The primitive archer might not literally "spine" a shaft, but he still understands that shafts of a certain stiffness will shoot better than those that are weaker or stronger, and that on the whole, slightly stronger is usually less erratic than one that is too weak.
The thinning of shoot shafts is probably one of the few examples, if not the only real example of arrow shaft "tuning".
If we tune anything at all, it will be the set-up, of which the arrow is just one component.

The mechanical aspects are the same bundle of potential variables that they always were, but we may now be better placed to be able to understand what is happening and so be able to make calculated adjustments with some degree of confidence.


What is the "archer's paradox"?

The term "archer's paradox" was coined because it was at the time not understood how an arrow could be aimed directly at the mark at full draw, yet be offline at brace height and upon returning to departure, but still recover and go where it had been pointed at full draw. This was the paradox.

Many, if not most of the illustrations which accompany this definition all too often have a tendency to add to the confusion by not usefully representing what really happens.
The most commonly quoted and misleading definition of paradox is that "the arrow bends around the bow and recovers to go where the bow is pointing".

This definition is not useful since it is more obviously natural and efficient to point the arrow at full draw directly at the target. 
This done, it is of no interest to the archer where the bow might be pointing, since it is not about to go anywhere.
But this presumes that we match our shafts with this in mind: that it should go where it has been pointed at full draw.

There are methods where it is normal practice to align the edge of the bow and then to register the point in elevation, but this method is often employed to accommodate a slightly stiff arrow which will go to one side of where it has been aimed.
There are also enough styles of shooting where the divergence of the line of aim from the line of sight is accommodated by aiming off to one side. This indeed is the norm with many long draw styles where due to the draw-length and consequent location of the anchor, the dominant eye cannot be brought directly into line with the shaft.

It may also be that the confusion in the first instance derives from Klopsteg's description of the arrow "snaking" around the bow, which on first sight is true enough but, if taken too literally, is open to misinterpretation. 
An understanding of the close relationship between the line of aim, the subsequent line of flight and a line drawn through the nodes of the arrow throughout the whole cycle, makes it clear that this still all too common definition of "going where the bow is pointing" is misleading.


What the well matched arrow should do.

When the arrow is loosed the force applied by the string causes the shaft to flex as it accelerates.
Since the shaft rests against the side of the bow and is not directly in line with the action of the bow the resulting sequence is this: 

The shaft immediately bends into the bow. 
Then as the mid point of the shaft passes the bow the shaft bends away from the bow. 
As the tail of the shaft clears the bow, the shaft bends again into the bow.

The shaft does not immediately stop flexing, but a well matched arrow shot from a bow, the bow having a well profiled cross section at the pass and a sensible pass width, the arrow being cleanly loosed, the shaft can recover more quickly and will not fishtail so far in its flight as will a poorly matched shaft or one shot from a bow with a pass that is too wide, a cross-section that is less favourable, a brace height that is too low or with a poor loose.

When the frequency and amplitude of this bending are in harmony with the forces applied by the bow, the arrow can recover quickly from the disruption caused by the initial acceleration.

When the shaft is aimed at full draw a line drawn through the shaft should be the same as a line drawn through the nodes of vibration in the recovering shaft. The arrow can then go where it was aimed at full draw.
The closer the spine match, the more cleanly and precisely the arrow will recover and go where it was aimed.

A notional line drawn through the action of a non centre-shot bow is not aimed at the mark.
The bow itself will always points off to the side relative to a line drawn through the shaft. 


What are the nodes of vibration?

Each arrow shaft has its frequency of vibration and it is the harmonising of this with the bow that allows the shaft to flex in paradox, recover and go where it has been aimed.

If we were to take a shaft and suspend it by one end and then strike it sharply in the centre of its length, it will vibrate in its natural frequency at that length.
The range of movement (amplitude) will be at its greatest at the centre of length and in proportion to the force applied.

As we strike the shaft further away from the centre of length, the amplitude of the vibration will diminish until some distance from each end of the shaft we find a dead spot where the shaft no longer vibrates when it is struck. 

These two spots are the nodes of vibration.

If we imagine a flexing shaft which is free as it would be in flight and if we were to take the fully curved "crest" and "trough" of one cycle of vibration and flip one of these over sideways and superimpose the one upon the other by registering the nodes, the mean line drawn through the nodes defines the uninterrupted line of flight.
The recovering arrow, on clearing the bow, flexes on either side of this line which in a spine-matched arrow is also the line of aim to the target.


How the nodes and the arrow act during paradox and recovery.

An understanding of the role of node alignment will help us to make sense of what is actually happening to the arrow in paradox.

When the shaft is aimed, the nodes are of course aligned as we would expect, along the shaft.
If we further consider the shaft sitting at brace height, it is also obvious that the shaft is not on the aimed line, but very much forced to the left (right handed archer) by the combined geometry of the bow width and brace-height.

When aimed shaft is loosed, the flexing of the shaft effectively reduces this offset at brace-height by immediately bending into the bow and then "unloading" into an opposite curve as it flexes away from the bow as the front end breaks contact with the side of the bow.


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## rohpenguins (Dec 2, 2012)

The first phase of bending into the bow takes the nodes out of line as the string accelerates the arrow nock then during the second phase the shaft "rebounds" from the "loading" of the first phase and flexes in the opposite direction, breaking contact with the bow and curving "around" the bow.

This movement, to the naked eye, would seem to reinforce the old adage about the arrow "going around the bow, straightening up and going where the bow is pointing", but in actual fact what the nodes are doing in a matched shaft, as defined by a line drawn through them as the shaft flexes, is beginning to return to the aimed line.

At this point the centre of the shaft is passing the bow handle with the maximum clearance. 
In the third phase of flexing back into the bow, as the tail end of the arrow clears the bow, the process of realigning the nodes with the aimed line is well underway and it only remains for the shaft vibrations (flexing) to quieten down as the arrow goes where it has been aimed.
A matched shaft will typically clear the bow in about one and a quarter full cycles of flexing and since the rear end of the shaft relies upon this flexing away from the bow of its rear end to obtain clearance, it is plain that if this cycle is even slightly out of step with the action of the bow, then we will probably hear the sound of the shaftment striking the bow .
When this happens we will usually find the shaftment marked with the signature of a dark line between the hen feathers where the tail of the arrow has struck the bow.

Although there is still residual flexing of the shaft, from this point onwards the nodes are aligned with the mark as the vibration in the shaft diminishes.

When the shaft is too stiff, the degree of recovery in the second phase of bending is less and so line through the nodes diverges from the aimed line while the arrow is still flexing and as the vibrations settle out the arrow will go some degree to the left of the aimed line.

When the shaft is too weak, the degree of recovery in the second phase of bending is greater and so the line through the nodes diverges slightly with the consequence that the shaft will go somewhat to the right. 
Another consequence of a weak shaft is that if the increase in flexing is too pronounced, we will see excessive continuation of flexing in the form of fishtailing flight.

By looking at the behaviour of the nodes we can easily see how the behaviour of the shaft in disruption of and recovery from paradox relates to the aimed line.
A line drawn through the nodes at full draw and when the shaft has cleared the bow will define where the arrow is headed at that instant irrespective of whether the shaft is flexing or not.


Unavoidable reactions.

In high speed recording we can see two types of reaction in the bow, neither of which should concern us unduly.

There is the reaction of the bow handle as the limbs come home, which causes a small movement against and away from the bow hand.
There is an out of line "following through" of the bow string when the arrow leaves.

Neither of these are subject to manipulation in the ordinary way; instead we can avoid introducing unnecessary variables into the process by being consistent in how we handle the bow.


How does spine affect the flight of the arrow?

A weak spine (underspined in American terminology) will flex more and will shoot to the right of the aimed line.
The weaker it is the more obviously it will fishtail in flight (wiggle left to right).

A stiff spine (overspined in American terminology) will flex less and will shoot to the left of the aimed line.
If very stiff it may yaw noticeably to the left.


What factors modify shaft spine?

Bow cross-sectional shape, the width of the arrow pass and the brace height should not be overlooked. 
Whilst it may be argued that these do not literally "alter" the spine, Which is not entirely true, they do have a significant effect on where the arrow will wind up going.
In the worst case the arrow can be so much effected by disruption that a degree of offset is produced which means that this combination cannot be set-up to shoot where it is been pointed at full draw without rethinking the manner in which it is handled.
Not that some cultures don't shoot in this way, those typically with wide and low braced short bows are probably the most obvious example, but it certainly places some limitation on how it is best used. Typically these would be used for close work, with a more "horizontal bow" style of shooting, which allows a "straighter" lateral alignment and making the inevitable lateral divergence (if the bow were held vertically) into a part of the existing solution in elevation. 
We occasionally see examples of "can't get an arrow of any spine to shoot straight out of this bow", which should really come as no surprise where the cause is too much pass width aggravated by too low a brace height.


A rectangular cross-section can increase paradox by increasing the amount the arrow is pushed off line at brace-height.
A rounded cross-section can reduce paradox by reducing the amount the arrow is pushed off line at brace-height.

An arrow pass which is longer from back to belly will not only effectively reduce the brace-height, but also if of rectangular cross-section, have corners which are more likely to interfere with the clearance of the flexing shaft as it leaves the bow.


A high draw-weight makes the shaft flex more and needs a stiffer shaft.
A low draw-weight makes the shaft flex less and will accept a weaker shaft.

A more efficient bow of the same draw-weight will shoot faster and need a stiffer shaft.
A less efficient bow of the same draw-weight will shoot slower and will accept a weaker shaft.

A narrower arrow pass will push the shaft less off line and will accept a stiffer shaft.
A wider arrow pass will push the shaft more off line and will need a weaker shaft.

A shorter shaft of a given diameter and point weight is functionally stiffer.
A longer shaft of a given diameter and point weight is functionally weaker.

A lighter point weight makes the shaft functionally stiffer.
A heavier point weight makes the shaft functionally weaker.

A lighter string will shoot faster and may accept a stiffer shaft.
A heavier string will shoot slower and may accept a weaker shaft.

A smaller diameter of shaft of the same spine will stand a little less off line and may be spined a little stiffer.
A larger diameter shaft of the same spine will stand a little more off line and may be spined a little weaker.

Small adjustments in brace-height are used to modify functional spine in basic bow set-up.

Raising brace-height reduces offset which reduces paradox, but it also slightly reduces the length of the power stroke which slightly reduces the arrow speed.
Lowering brace-height increases the off-set which increases paradox, but it also slightly increases the length of the power stroke which slightly increases arrow speed.


Margins of error.

The margin by which the flexing shaft clears the bow can vary, but is not so great that it will not be adversely affected by small changes in any of the possible variables. 
If the spine selection is hypothetically correct or within limits, but the arrow still does not shoot as well as we might like, selecting arrows of another spine is not the only choice.
A remedy can often be found by manipulating the set up variables; the simplest and first option usually being to adjust the brace height. 

We often cause the problem in the first place by not having paid sufficient attention to the geometry of the bow and how it is set up.

But our choices are not always determined strictly by function. It is just as likely that we might choose a bow for cultural reasons; but if our choice is not functionally determined, then it follows that we accept and adapt to the idiosyncrasies of the chosen style, perhaps adjusting both our technique and our expectations.

It is also important that we should not fall into the common habit of blaming the equipment for every apparent fault in the shooting.

Most problems with where the arrow goes are produced by how we shoot the arrow, or by a choice we have made regarding equipment and set-up.


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## rohpenguins (Dec 2, 2012)

The above article was written by Rob Parsons


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## tmorelli (Jul 31, 2005)

Nothing against Rob but that is pretty old-school thinking (outdated; case in point being his explanation of bare shaft POI with stiff/weak) based on cushion plungers and tuning the bow to the arrow.

There's another way to do it and it involves tuning the bow to the arrow. 

Great results can be had by either. I've used both. When I can, I prefer the stiff arrow and the bow with managed nock travel.


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## jwshooter11 (Aug 18, 2006)

So, not to hijack the thread or anything, but how does rest position affect all this? In other words, where should the arrow sit on the rest at full draw in relation to the node? Also, if someone could explain how to find the node on the arrow?


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## N7709K (Dec 17, 2008)

What arrows? Alus tune best with the node at or infront of the blade, carbons don't really matter. Nodes are the resoance points- the front one is the one that matters in finding correct arrow length. Plucking the arrow against a solid surface is the easiest way- you're looking for the dead spot.

That said, centershot in relation to the dynamic spine matters way more.


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## Fury90flier (Jun 27, 2012)

you want the rest to sit in a position where it places both front and back node are in line with the string and target. There is also getting the rest set forward/backward vs the front node location....- the closer to the node you get it, the more forgiving of torque- (at least that's my understanding)
finding the front node.
take your arrow- hold it by the nock- find a table edge- lay the arrow on the edge of the table about 1" from the point---pluck the arrow---see how it bounces off the table---now move the arrow along the edge of the table- plucking- as you move the arrow that bounce will increase or decrease- then there is a spot where the arrow won't bounce- that's the front node.


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## jwshooter11 (Aug 18, 2006)

So, you're saying that it's more forgiving if the node sits on the rest at full draw?


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## tmorelli (Jul 31, 2005)

jwshooter11 said:


> So, you're saying that it's more forgiving if the node sits on the rest at full draw?


Good luck proving that one out.

Take a gander of every bowjunky photo you can find of a 3d pro worth his salt. His arrow is cut within 1" of his rest and most will be less. I can guarantee you that the node is well behind the rest.

Torque tuning is not about aligning the node and the rest. It is about aligning the rest and the sight. Moving the rest back is not a requirement in torque tuning...it's an option and testing either says you should, or you shouldn't and the opposite may be required (moving the rest foward....or the sight in).


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## jaydub (May 16, 2008)

Great discussion.


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## jwshooter11 (Aug 18, 2006)

I was thinking the position of the node would have more to do with the up and down variation due to how it reacts with the rest. As far as 3d pros, I shoot in that class. For the most part, guys cut their arrows 1/2" in front of the rest. IMO, this has more to do with speed. I do the same thing on my 3d bow. I'm referring to my bow that is set up for field/FITA/indoors.


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## tmorelli (Jul 31, 2005)

For anyone with a decent draw length, it would only be about speed in the IBO. 

I run closer to "ideal" spine on my field/fita arrows but still disregard the placement of nodes vs the rest...and still err stiff. I've done a lot of experimenting with breaking them down and don't see any improvement in scores. I'm currently running a 340 spine cut to the rest with 150 up front (fairly stiff per the software programs for me...but they don't act stiff). I worked a lot of combos (shaft length/point weight) in the 350-390-400 spine ranges and never saw an increase in forgiveness that equated to score over a season of shooting field rounds with the various configurations.


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## jwshooter11 (Aug 18, 2006)

tmorelli said:


> For anyone with a decent draw length, it would only be about speed in the IBO.
> 
> I run closer to "ideal" spine on my field/fita arrows but still disregard the placement of nodes vs the rest...and still err stiff. I've done a lot of experimenting with breaking them down and don't see any improvement in scores. I'm currently running a 340 spine cut to the rest with 150 up front (fairly stiff per the software programs for me...but they don't act stiff). I worked a lot of combos (shaft length/point weight) in the 350-390-400 spine ranges and never saw an increase in forgiveness that equated to score over a season of shooting field rounds with the various configurations.


I'm running almost exactly the same setup on my field rig. I'll play with that some today and see if it makes a difference.


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## N7709K (Dec 17, 2008)

Nodes matter for alu's- pretty much what it comes down to, they flex slightly different and provide better results when the node is at or infront of the the blade. With carbons unless they are severely stiff with longer shaft lengths and heavy tips(xxx's for example) getting the node on the rest doesn't gain anything measurable. Now if you shoot short dl or low poundage tuning needs to be different.

Slightly weak will have closer misses and less x's, stiff with have tighter groups but misses will be farther out- depending on game one works better than the other. There is no true "ideal" that works for all games in all situations; you can get close by tuning arrows to your rig and then figuring the dynamic spine of those arrows so subsequent batches are made accordingly. Each game takes a different optimal spine and what you are after take the same thing: is it inners or big 10's? Outdoors is it 700's or no 8's?


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## bigHUN (Feb 5, 2006)

jwshooter11 said:


> ....how does rest position affect all this? ....


The rest position (meaning = height) is driven by the nocking point height. The nocking point travel (look for a nock point drawing board) is most straightest if the string above and below have a same length moving along the CAM curvature/circumference. If the two Cams are out of sync may be a less error than the Cams are not the same geometry, for both cases what we want a straightest nocking point travel and we will do the tuning according to....what Cams we have there....
The rest position (L-R) is mostly driven by the spine / flex amount of the arrow at the moment when the nock is already in motion but the point is still static, assuming the Cam axles are parallel (means Cams are inline). 
I may be wrong and I will accept your input any time  
I chose my bows not by speed or appearance or popularity but easy tuneability and a minor CT and FT combination will do the job quickly and effectivelly, and for all these no press is needed.


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## bigHUN (Feb 5, 2006)

tmorelli said:


> ....There's another way to do it and it involves tuning the bow to the arrow. ...


I agree with you totally, 
My game is limited to 59.9 lbs maximum DW and I don't want to shoot less than 56 lbs, so my goal is about 58ish lbs but I want my holding weight to be 22-23 lbs. These restrictions I put into my calculation and the result must be within 1" maximum tolerance in total. What means I will work on both the arrows and the bow in the same time.


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## tmorelli (Jul 31, 2005)

bigHUN said:


> I agree with you totally,
> My game is limited to 59.9 lbs maximum DW and I don't want to shoot less than 56 lbs, so my goal is about 58ish lbs but I want my holding weight to be 22-23 lbs. These restrictions I put into my calculation and the result must be within 1" maximum tolerance in total. What means I will work on both the arrows and the bow in the same time.


I typically don't alter my draw weight or holding weight when tuning to a stiff arrow. All that is required is removal or management of nock travel.


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## ron w (Jan 5, 2013)

correct,..
the arrow flexes through the node as the epicenter of the flex. when the arrow sits on the node, flex has no impact on how the attitude the arrow leaves the bow. the reason it is said that contact should be at, or in front of the node is because as the arrow flexes with the node behind the rest, it flexes the arrow up and the arrow relaxes in an upward path or attitude from the Cg being lifted during the flex. 
when the node is in front of the rest, it flexes up and the CG drops slightly and when the arrow relaxes the rest pushes the arrow back into it's intended attitude as it leaves the bow.
a stiff arrow simply doesn't flex as much, so it's attitude is less altered, regardless of where the node is in relationship to the rest.


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## hobz (Jan 18, 2013)

why does the shaft bend "into" the bow if the only point of contact on a modern compound bow is the rest directly beneath the arrow? shouldn't the arrow flex in that direction? rather than perpendicular to it


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## ron w (Jan 5, 2013)

the offset from a cable guard, influences the path that the string takes in relation to the center shot of the riser through cam lean. this influence directs the direction the arrow flexes, horizontally. eliminating the lean, cleans up the vertical travel and reduces horizontal shaft flex. an arrow flexes both up, away from the rest and away from the riser.


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## edgerat (Dec 14, 2011)

jaydub said:


> Sorry if it isn't the correct forum. Im sure it will get moved. I will with hold my reasoning for putting it here. accordingly. If an arrow flexes between nodes by design, how is a perfect paper tear possible at all distances? I cant get past that.


Not at all distances but out to a certain distance it is possible, that is how I tune my setup. Bullet hole at point blank (bareshaft) and then at 20y. Most arrows do not ever stop flexing in flight. Some call this controlled arrow flight and frown on it, I have personally seen the benefits of tuning this way and having a spine that can be "broken down" by the bow, why not give yourself every advantage you can?


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## bigHUN (Feb 5, 2006)

A good reading could be find here:

http://www.archerytalk.com/vb/showthread.php?t=382001

also, worth reading couple more minutes:

http://www.archerytalk.com/vb/showthread.php?t=1537989


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