can someone explain spine thoroughly?

[thegreatwhale]

so i know that the spine is related to the poundage of the bow, but what determines that? is it the thickness? the weight or density of the shaft? the length of the shaft? what is it that dictates spine? any help in this is much appreciated!
-kegan

[osage outlaw]

Its the stiffness of the shaft.  Basically how much force it takes to bend the arrow.  Its measured by supporting an arrow 26" apart and measuring how much it bends with 2 pounds of weight applied in the center.  The more it bends the lower the spine.
Maybe somebody can give a more detailed explanation.

[Danzn Bar]

OO that is a very good explanation of arrow spine, and a real great place to start looking for an arrow to shoot well from your bow. Dramatic spine (shooting and arrow) has a lot to do with the bow your shooting, length of arrow and weight on the point.
DBar

[CORIUS]

Heres a link that really helped me out.

http://poorfolkbows.com/spine1.htm

[bubbles]

I think you mean Dynamic Spine Danzn bar.   .  It is the  stiffness of the shaft as has been said before.  A thicker shaft, or a denser shaft or even an shaft that has a straighter grain will be stiffer in spine.  This can be measured with a spine tester as has already been mentioned. Dynamic spine is more difficult to measure as it comes into play as the arrow is being shot.  A longer arrow shaft and a heavier tip will DECREASE the spine of your arrow. This is simply because a longer piece of wood flexes more easily than a shorter piece of wood.  A heavier point will decrease spine because of the increased inertia of the heavier point. Push a 1 lb weight across the floor with an arrow shaft, then push a 25 lb weight and see the difference in flex. This is an extreme example, but it illustrates the point. 
You want to match the spine of your arrows to the poundage of your bow, that way, when they are shot, they flex just the right amount to shoot straight out of your bow, with no tail wagging.  Sorry about the long reply, I'm just really bored  at a wedding waiting for these damn speeches to finish.    is there a better way to pass the time than talk about arrow spine?

[bow101]

One more thing Wooden arrow shafts have to be spined against the grain.

[stickbender]

     What Osage Outlaw, bow 101, Corius, and Bubbles, said.  It is the stiffness of the shaft, versus the strength of the bow.  When the arrow is shot from a bow, it does not just go "straight as an arrow", it first flexes, or bends.  The weaker the spine, vs. the strength of the bow, the more bend, or flex, and more time, distance, etc. it takes for the arrow to recover, and fly straight.  This where the fletching comes into being important, as it helps the shaft to recover.  The more the spine weight, and the bow weight, or strength, are matched, the better the flight, as the arrow recovers quicker.  This is more pronounced in an off hand bow, than a center shot, or bow with a shelf, as the arrow has to bend around the bow, "AND" recover.  Also the natural arrow shaft material, has a strong side, and a weak side.  The strong side goes against the bow, and it is that side that is measured for spine.  Anyway, that is "MY" understanding of it.  The more your arrows, match in spine, and shaft weight, and length, the better and more consistent your grouping will be.  Which is why a lot great bowers, prefer making bows to arrows, and would rather buy, or trade for them, from those who like to make arrows.    A lot of work goes into making the arrows.  A lot more variables to consider.  I hope this, along with what  the others have said can clarify it for you.   

                                                                  Wayne

[Danzn Bar]

I think you mean Dynamic Spine Danzn bar.   . 

Yeah...that's what I meant bubbles........... one toooooo many barley pops  last night.    
DBar