Changing Arrow Spine

PLEASE HELP TO FUND ARCHERY INTERCHANGE

albatross

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I have just completed a spine check on my Easton ACC arrows. I was curious to see if having shot them for approximately 2 years whether the spine had changed. I suspected that there would be some change due to 'work hardening' of the aluminium core due to the continual flexing during release/flight. I used my spine checker and got the following values. New unused ACC 2.04 920 shaft deflection = 18.43 mm. Used ACC 2.04 920 shaft deflection = 17.39mm. So it looks as though they did stiffen during use and maybe they are too stiff for the rated poundage range (Easton white chart). Any comments?
 

albatross

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Thanks for the reply. I will have to make up a 'new' set of arrows and compare how they behave. Has anyone else found their arrows get 'stiffer' with use?
 

Timid Toad

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I rather find it's irrelevant comparing new with old as I don't mix sets if I can. The acid test is whether or not they tune with what I want to shoot. If the do, fantastic, off we go. If they don't, they are retired. Anything else is rather over thinking things.
 

Timid Toad

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Never bothered trying to measure.
At some point, they don't group any more and I get rid of them.
Quite. It's really possible to spend more time focussing on kit when just shooting it will (a) tell you more and (b) improve your shooting.
I do shoot a bare shaft in practice with each set of arrows I have which shows up form changes and if something has changed on my bow (such as something coming loose) but apart from that, the more arrows I can shoot the better it is.
 

Stretch

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100% agree with TT and Shirt. If anything I found arrows got weaker as straw bosses wore down the carbon.

When they stop grouping move them to the blank boss trash pile.

For any new set cut them long - see how it goes. Trim them - see how it goes. Etc. Once very close, use minor weight changes to get it where you want it. Every time.

In days gone by I’d strip them all and bareshaft them all together periodically… but not any more… because I am lazy.

Stretch
 

Whitehart

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I agree with TT & S - don't group might just use them if still safe to shoot to keep the arrow count up especially into straw.

Some say that AC arrows take a bend (get used to flexing a certain way)after a lot of use I don't know if this is true not had the inclination to find out but since you have posted and doing all the work :) , when you measured them were the shafts the same orientation, as there could be a weak and stiff pointside???????
 

Whitehart

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If this worries you, regularly rotate the nocks.
Does not worry me but raises an interesting point, I do rotate nocks (before fletching and check the grouping once fletched which sometimes also requires a nock to be rotated) with a new set of AC shafts, so they all group together- surprising how many fliers you get even with x10's. Maybe worth rotating the nocks and re-checking groups before consigning a shaft to the bin.
 

Thorvald

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A bit interesting topic. Spine 920, should flex 0,92 * 25,4 = 23,4 mm - but your measurements are much lower - much stiffer. Similar to 18 / 25,4 = appr. spine 700. ???
 

Timid Toad

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A bit interesting topic. Spine 920, should flex 0,92 * 25,4 = 23,4 mm - but your measurements are much lower - much stiffer. Similar to 18 / 25,4 = appr. spine 700. ???
Depends on the length of the arrow, the spine checker used and the weight used. It'll only be standard to the Easton charts if it's measured the same way as Easton. A shorter arrow, for example, will deflect less, and it won't be possible to measure at standard conditions no matter what other standards apply.
 

Thorvald

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Hmmm - don't get that. There is a standard for measuring the spine. I assume this standard is the same for all: "Spine ratings are determined by taking an arrow shaft at a length of 28”, supporting it at both ends, and hanging a 1.94lb. weight at the center. The amount of flex that is induced on the arrow shaft by the force of the weight is then measured and gives us our “static” spine rating. For example, if an arrow bends one-half of an inch at the center, then the shaft has a static spine deflection of .500”."

Source: This link.

But of course if your arrows are shorter than 28", you can't do that. I was just wondering why your unused shafts did not get the correct spine. :)
 

Timid Toad

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Hmmm - don't get that. There is a standard for measuring the spine. I assume this standard is the same for all: "Spine ratings are determined by taking an arrow shaft at a length of 28”, supporting it at both ends, and hanging a 1.94lb. weight at the center. The amount of flex that is induced on the arrow shaft by the force of the weight is then measured and gives us our “static” spine rating. For example, if an arrow bends one-half of an inch at the center, then the shaft has a static spine deflection of .500”."

Source: This link.

But of course if your arrows are shorter than 28", you can't do that. I was just wondering why your unused shafts did not get the correct spine. :)
Lots of people make their own, and the only way to know what they have is to compare apples with apples.
 
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