Aside from the added point weight, could a collar otherwise affect the spine of an arrow?

CNP Mike

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So hear me out. We all know that adding weight up front weakens the spine of an arrow. We know that shortening an arrow stiffens the spine. What I haven’t found any information about, is how having a footer or collar of a certain length might affect the spine of an arrow; aside from the added point weight. So if you are under spined with a 28” arrow but in the sweet spot with a 27” arrow, how would a 1” or 1.5” collar (possibly even a longer insert) affect the rigidity of said 28” spine?
 
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ozyclint

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having a footer does affect dynamic spine once the footer extends past the rear of where the insert is. it's the same as trimming your arrow without trimming your arrow. it's an under utilised option for tuning IMO.
from my trad experience the added weight has far less effect on spine than the extra length of a footing
 
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Longer inserts will act like a footer, but they aren't the same as a shorter shaft either. Determining it is difficult. A shorter shaft stiffens the arrow a lot more than adding an insert of the same length that you would cut off. You will need to shoot everything to figure out where it is. I feel like the footer/long insert is around 1/2 the length off the shaft. So if you have a 3" insert, that puts it 2" longer than a standard insert, it's like loosing 1" of shaft, or half the difference.

Edit to add:
A 1" collar isn't changing anything. A collar that is 1/2" longer than your insert you might notice tuning a trad bow, but I doubt it. For compounds I'd ignore it.
 
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Zac

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I've wondered the same thing. Snyder said a shooting machine can't tell the difference. Bill V also said it makes no difference.
 
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I've wondered the same thing. Snyder said a shooting machine can't tell the difference. Bill V also said it makes no difference.


That's not exactly what Bill said, he said the static spine remained the same. He figured that it did change the dynamic spine.

I haven't ever seen static spine change when you are cutting arrows down, until you get less than 28" where they don't contact the points anymore. Now take an arrow of the same spine, and measure deflection at 32,31,30,29"..... The deflection gets smaller and smaller as you get shorter. These long inserts are changing the amount of spine that is available to flex, so in my mind they have to be changing the dynamic spine reaction to some degree, just like a footer does. How much?? I haven't been able to quantify. I think the half the difference like I tried to explain above is close, but probably not entirely correct and has more to do with a percentage, so it's different with longer and shorter arrows.
 

jmez

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Geez, all this talk about spine. In 35 years of shooting bows I have never had arrow spine be an issue. IMO it is the most over rated and over blamed variable in archery.
 

Scoot

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I agree with jmez, to a point. It's not a problem, until it's a problem! About 90% of the time (or more) that it is a problem, it's due to being underspined. Overspined rarely causes issues (but occasionally does).
 
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