# dumbest arrow shaft size & spine question ever asked...



## rgauvin

I see all the numbers thrown around and being totally new to archery it makes my head spin. I understand that there are difference size arrows, and different spines, but how can a newb like me figure out what the numbers mean?


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## Dave T

When I was in your place (a few years ago) I got an arrow shaft maker's catalog and a couple arrow charts and just set down and studied them. Took a while but the patten of it all started to fall into place eventually.

Don't feel bad. You're not the first and won't be the last who is confused by it all. Some of us still buy the wrong arrows at times...I just did! (LOL)

Dave


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## Jim C

on easton aluminums its simple

2114 means 21/64 outside diameter while 14 means the wall thickness 14/100s

ACE AND X10

its spine 570=570 spine
same with McKinneys

ACC is a bit more complicated

3-39 means a 3 wrap of carbon and size 39-the bigger the size the stiffer the arrow

note the real spine (I think 3-39 is 520 or so) is printed on the shaft

spine-the higher the number the WEAKER THE SPINE because its the amount of deflection a shaft bends with a certain amount of weight hung on the shaft


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## Ohio_3Der

*answers*

Aluminum:

Example, 1816. The 18 would be the outside diameter in 64ths of an inch and the 16 would be the thickness of the tube in thousandths of an inch. Spine would be undetermined by the name alone, but would be easily looked up.

Spine is determined by how much a shaft flexes. They set the shaft on two v blocks 28 inches apart and hang a specific weight from the middle of it. The spine value is the distance the shaft flexes from straight. So, the bigger the spine value, the weaker the spine in the shaft, or the more flimsy it is. 

It is SPINE not SPLINE! 

In carbon arrows, sometimes a name will tell you the spin of the arrows. Like, for example, beman ICS arrows are named 340, 400, and 500. Those are those arrows spines from stiffest from weakest. But, in other company arrows, like carbon express, they don't use this system. Carbon express has a 100, 200, and 300, but the 300 is the stiffest, so those numbers are just arbitrary. 

Most carbon arrows with internal components are the same size in ID diameter and OD diameter as an Easton ACC 3-60. That's the same outside, OD, diameter of an 1816, or 18/64ths. 

Easton also has redline arrows, and they are named by spine. Like the flimsy/weak 1000. ACE's are also named like this. 

I hope this fills in a few blanks. 

Just remember that the wall thickness contributes most of the weight and the outside diameter contributes most of the spine.


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## Ohio_3Der

*whew*

all the other guys were posting as I was typing....


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## VFX_Fenix

Aluminum Arrows from Easton, and a few others, give their shaft sizes as a set of four numbers (i.e. 1916). The first couplet is the shaft OD in 64ths of an inch (e.g. 19/64"). The secound couplet is the wall thickness in 1000ths of an inch (e.g. 0.016"). If I'm mistaken, someone please correct me on this. :darkbeer: 

Carbon arrows come in a few different flavors, but all of the sizes as far as I'm aware represent the shaft's static spine. The static spine is measured by taking a shaft of a fixed length and having it span a gap of I believe 29" with a weight suspended from the middle of the shaft (something around 1.9lb but its a standardized weight that's used) and how much the shaft bends from true is the shaft's spine number. So a shaft that bends .600" from true under load has a 600 spine.

Easton, and a good number of other companies, takes this spine number and slaps it on their shaft. So an Easton RedLine 600 has a static spine of .600". I believe this is also true for some of Easton's Aluminum/Carbon hybrid shafts and Easton's Game Getter II.

Another method of giving spine on a carbon shaft is more in the tradition of the way Aluminum shafts are labled (bigger numbers = stiffer shafts). Carbon Express (CX) and PSE use this method. So a CX100 shaft is weaker than a CX300 shaft. Be aware that CX also does use the Easton method for their NANO-XR line of shafts.

Yet another method for carbon is used by GoldTip (GT) there they more or less give the size of the arrow in terms of the bow weight that it can be shot from. This is in the tradition of wood shafts and a GT3555 means, roughly, that the shaft is appropriate for a 35lb. to 55lb. bow.

Satelite uses a variation on the above method and gives a shaft series number (I believe) and then a maximum bow weight (i.e. a Satelite 2980).

I think that's all of the methods used to lable arrows that you'll commonly run into.

Making heads or tails of it, well that's something completely different, kind of.

Be aware that just because you can shoot a shaft of a given size/spine from one company doesn't necesarily mean you can shoot the same size shaft from another company. The dynamic spine (how the arrow behaves when put under a load with a point/insert/nock/fletching) may be different because of differences in components used between the shafts. Rule of thumb, more weight on the front of the arrow weakens it and more on the rear makes it stiffer. So unless the components are identical between the two shafts, one shaft may behave differently.

I'm sure I've gotten something wrong along the way, the folks here will straighten me out though. :wink:

EDIT - I'm with you on this one Ohio.... :lol:


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## WoolyWelsh

*Welcome to the fray!*



rgauvin said:


> I see all the numbers thrown around and being totally new to archery it makes my head spin. I understand that there are difference size arrows, and different spines, but how can a newb like me figure out what the numbers mean?



IMHO, there are no _dumb_ arrow shaft size & spine questions on AT. We all have to start at the beginning. Just make sure your head has right-hand threads, it'll stay screwed on tight! :wink:


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## Progen

WoolyWelsh said:


> ... Just make sure your head has right-hand threads, it'll stay screwed on tight! :wink:


What if he's shooting left handed? :wink:


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## StarDog

Oh thank god someone posted this. I was about to ask the same question. Usually I just "rely on the kindness of strangers" and ask my coach what to do but I got really really clever the other day, and actually made my own decision of a set of arrows!

So, having discussedd it with the pundits at the range where I shoot, I figured out that

spine is inversely proportional to the draw weight of the bow, except in the case of x10's (of so I was told).l

Or something like that.


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## VFX_Fenix

Ummm... Yep, higher draw weights = lower spine numbers. 

The X-10 is the same though as the number on the shaft (i.e. X-10 1000) is indicative of the static deflection of the shaft. So an X-10 550 (0.550" deflection) is stiffer than an X-10 1000 (1.000" deflection).

CX and PSE use higher numbers to indicate stiffer arrows (i.e. a CX300 is stiffer than a CX100).


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## limbwalker

I sure wish every carbon manufacturer would just go ahead and accept the same standards of deflection to measure shaft spine. Sure would make it a LOT easier on the rest of us.

At least Rick and it appears Carbon Express now with their nano shaft, have seen the logic and classify shaft spine based on the deflection measurement.

John.


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## Guest

I used to hate the idea of spin "deflection" as a measurement for the right shaft selection. But, as shafts have become more expensive I see the wisdom and use it. 

Now if I could just find a spin measuring devise that is accurate and shows the deflection.

New shaft selection program on Eastons web site I understand is pretty accurate.

Make sure you have an accurate measurement of your draw length and the poundage on your bow then just go by the manufacturers suggest shaft.
You will still have to fool around with point weight and length but you will be starting close.
Art


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## Guest

Here's a question. Will spin deflection on Aluminums match the spin deflection on carbons.

In other words if you have some alum. shafts that are perfectly spinned for your bow. Can you just match a carbon shaft with the same deflection and have it shoot as well as the aluminum?

Art


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## 88 PS190

I recommend downloading and using On Target 2 to compare these things.

What I will go into now is Static spine vs. Dynamic spine.

Static spine is the number measured of the deflection of the shaft as was noted above across a 28" span w/ a specified weight.

say this is a .500 static.

Dynamic is what that arrow does when shot, or how it behaves. This is effected by the tip weight, fletching weight, nock weight, bushings, wraps. As well as shaft length and the bow settings its being launched from.

When setting up carbons vs. aluminums technically an aluminum that has its dynamic spine adjusted to match the dynamic spine of a carbon will shoot the same, though the arrows might have different characteristics.

One of them is FOC. I can take a carbon arrow, say a Gold Tip 500, and spine that to a bow and get an FOC of around 8.5% (3D arrow) Then I could also take a stiffer aluminum arrow, and add more tip weight to reach the same dynamic spine, but the FOC on the aluminum would be different because of that heavy tip.

So shafts that are perfectly spined to your bow, are perfectly spined to your bow, but will have different characteristics.


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## rgauvin

wow, thanks for all the great answers guys. It gives me something to learn and try to start with. 

Here I was thinking I was gonna get flammed, but man there is alot to learn about specs, sizes, etc, and that is just the arrows  Learning all this is almost like work lol


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