fletching question

[paulaboutform]

Does it matter where the 'cock' vein is placed on the bolt. I've always lined them up with the graphics but was wondering if there's a seem or something that gives better results? Thanks for the info.

[Normous]

A spine testing machine would determine spine and the best place to locate your cock feather to improve accuracy and uniform groups.

[Galgo]

Enormous could you explain how determining spine shows you cock vane placement. Never understood that. Isn't spine just a measurement of flex? Thx.

F

[Normous]

Some past info here:
http://www.excaliburcrossbow.com/phpBB2 ... ne+testing
Boo may chime in with additional information.

[Bullzeye]

Here is a thread by Boo on the Subject.

http://www.excaliburcrossbow.com/phpBB2 ... lit=tester

[Galgo]

Thanks guys this makes more sense now. I guess static spine as Boo referred to it is the stationary amount that and arrow will bend over a certain length when a certain weight is applied. Probably more relevant to Vert bow shooters in relation to draw length (arrow length) and poundage. Too stiff and an arrow can break on launch (seen this - not pretty) too soft an an arrow would wobble too much during flight adversely affecting gyroscopic inertia and stability thus accuracy.

Where the other spine is more of a result of the manufacturing process which applies more material in one spot on the length of the arrow. I guess an analogy to this could be where the material would overlap (like folding piece of paper into a tube) there is more material along the spine than in the "soft" spot that Boo mentioned.

Makes sense that putting the cock vane along the spine would give the arrow a more consistent flex and perhaps less flex once it is shot.

I ask arrow building aficionado's to please correct the above if I have things wrong. That will help me sleep tonight

F

[paulaboutform]

Thanks guys this makes more sense now. I guess static spine as Boo referred to it is the stationary amount that and arrow will bend over a certain length when a certain weight is applied. Probably more relevant to Vert bow shooters in relation to draw length (arrow length) and poundage. Too stiff and an arrow can break on launch (seen this - not pretty) too soft an an arrow would wobble too much during flight adversely affecting gyroscopic inertia and stability thus accuracy.

Where the other spine is more of a result of the manufacturing process which applies more material in one spot on the length of the arrow. I guess an analogy to this could be where the material would overlap (like folding piece of paper into a tube) there is more material along the spine than in the "soft" spot that Boo mentioned.

Makes sense that putting the cock vane along the spine would give the arrow a more consistent flex and perhaps less flex once it is shot.

I ask arrow building aficionado's to please correct the above if I have things wrong. That will help me sleep tonight

F

How can you determine this without a spine tester and how critical is it?

[Masboy]

If you can buy your arrows from someplace that they mark the spine that,s a good start. I do this when I can but not always an fine to get the best shooting arrows I can get because I have no spine detector I number each arrow an vane an I shoot each arrow over an over with every vane tryed for the cock vane an fine the one that shoots the best group an close the same poi as most of the rest of the arrows.

On good arrows with the right vane as the cock vane you will see great groups an a pattern where they hit close for poi. it takes time but you can get some great shooting arrows this way an not have as many flyers . I guess most arrows will hit deer vitals at normal hunting ranges without being spine marked but I just like have the best flying arrows I can make with the same poi an great grouping with fieldpoints an broadheads.

[paulaboutform]

If you can buy your arrows from someplace that they mark the spine that,s a good start. I do this when I can but not always an fine to get the best shooting arrows I can get because I have no spine detector I number each arrow an vane an I shoot each arrow over an over with every vane tryed for the cock vane an fine the one that shoots the best group an close the same poi as most of the rest of the arrows.

On good arrows with the right vane as the cock vane you will see great groups an a pattern where they hit close for poi. it takes time but you can get some great shooting arrows this way an not have as many flyers . I guess most arrows will hit deer vitals at normal hunting ranges without being spine marked but I just like have the best flying arrows I can make with the same poi an great grouping with fieldpoints an broadheads.

Is there any way to tell by looking at the shaft?

[Masboy]

Not on carbon that I know of. But on aluminum I have great luck by puting the cock vane on the seam that runs down the arrow. I know aluminum don,t seem as picky about where you put the cock vane.

[Galgo]

I have been building my own arrows for only three years now and I have never worried about it. But generally one in six arrows that I make does not shoot well. I will try to determine spine when I make my next set and if I have consistency issues I will try different vanes as cock vanes but so far without worrying about spine I am very happy with my accuracy.

Just my opinion about what works best for me

[nchunterkw]

If you can buy your arrows from someplace that they mark the spine that,s a good start. I do this when I can but not always an fine to get the best shooting arrows I can get because I have no spine detector I number each arrow an vane an I shoot each arrow over an over with every vane tryed for the cock vane an fine the one that shoots the best group an close the same poi as most of the rest of the arrows.

On good arrows with the right vane as the cock vane you will see great groups an a pattern where they hit close for poi. it takes time but you can get some great shooting arrows this way an not have as many flyers . I guess most arrows will hit deer vitals at normal hunting ranges without being spine marked but I just like have the best flying arrows I can make with the same poi an great grouping with fieldpoints an broadheads.

Is there any way to tell by looking at the shaft?

Look at the post by Bullzeye. In the link, Boo shows how to use 3 bearings to find the spine of an arrow.

[nchunterkw]

I have been building my own arrows for only three years now and I have never worried about it. But generally one in six arrows that I make does not shoot well. I will try to determine spine when I make my next set and if I have consistency issues I will try different vanes as cock vanes but so far without worrying about spine I am very happy with my accuracy.

Just my opinion about what works best for me

I'm about like you Galgo. I started checking spine and got a few arrows back. What helped me more was squaring the bare shaft and then the nocks and inserts after install and before fletching. "Good enough" for me is 4 arrows in about a 1" group at 40 yards with my BH of choice on them. I shoot a variety of fixed blades. My opinion is that a well made arrow shoots a well made fixed BH very well.

[Galgo]

Today I spun my arrow on the spinner and found that that all "settled" at a particular point. I am assuming (i know) that they are settling where the maximum amount of arrow material along its length pulls the arrow to the bottom. \i marked that bottom side as the spine and will place my cock fletch there and see what happens.

F

[paulaboutform]

Today I spun my arrow on the spinner and found that that all "settled" at a particular point. I am assuming (i know) that they are settling where the maximum amount of arrow material along its length pulls the arrow to the bottom. \i marked that bottom side as the spine and will place my cock fletch there and see what happens.

F

Great idea. Please update with your findings.