Too Stiff a spine theory exploration
09-20-2002, 11:40 AM
#11
Fork Horn
Join Date: Feb 2003
Location: Klamath Falls, Or
Posts: 300
RE: Too Stiff a spine theory exploration
An arrow when shot from a release will oscilate in the verticle plane if spined correctly. It doesn't matter if you are shooting it from a prong rest or fall awat you will get the same reaction. If the spine is too stiff the arrow won't bend properly. This causes the tip of the shaft to push to the left side. That is represented in the point left tear in paper. You can tune a stiff shaft to shoot bullet holes by moving the rest right of center, this will compensate for the stiff reaction. By doing that you now have a situation where the force of you're bow is directed along the "center of the bow" you're arrow is nolonger alinged in that center(you're center shot has to be off compensate for the stiff reaction) To get the most efficent transfer of energy you must have all you're little ducks in a row. I have seen all of this with high speed camera video. It was a real eye opener to see the arrow reactions slowed down like that. Watching the video you can see the carbon arrows recover very quickly. within a few feet of the bow the verticle oscilations have stopped and the arrow is flying true. If the spine is to weak you will get into the paradox situation. the shaft bends wildly back and forth and causes all kinds of problems.
amosgreg: The reaction will be the same. The horizontal oscilation reaction is caused by the string slipping off the fingers. This causes a side to side string oscilation and the arrow just follows along. That is why finger shooters use a side pressure rest. The arrow simply bends around the plunger as it leavs the bow. The reaction is not caused by the rest but by the fingers. With a fall away rest the same principles apply. The rest is not what causes the bend in the arrow. What causes the arrow to bend is the application of force to the nock by the string. the string pushes on one end of the arrow and the tip resists that acceleration. That is why the shaft bends. I hope I am clear in my answer
I will try to find the name of the video with all the slow motion photography and post it. It had some great explinations along with the video.
Andrew
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amosgreg: The reaction will be the same. The horizontal oscilation reaction is caused by the string slipping off the fingers. This causes a side to side string oscilation and the arrow just follows along. That is why finger shooters use a side pressure rest. The arrow simply bends around the plunger as it leavs the bow. The reaction is not caused by the rest but by the fingers. With a fall away rest the same principles apply. The rest is not what causes the bend in the arrow. What causes the arrow to bend is the application of force to the nock by the string. the string pushes on one end of the arrow and the tip resists that acceleration. That is why the shaft bends. I hope I am clear in my answer
I will try to find the name of the video with all the slow motion photography and post it. It had some great explinations along with the video.
Andrew
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09-20-2002, 01:02 PM
#12
Nontypical Buck
Thread Starter
Join Date: Feb 2003
Location:
Posts: 2,994
RE: Too Stiff a spine theory exploration
Why would a straight ahead release of a very stiff arrow cause the tip to go left? The force is being applied straight ahead, I'm having problems seeing how it would go anywhere but straight ahead.
Per Bob Ragsdale: "What are the ill effects of OVERSPINE with a really "straight ahead" launch?
Dear Glenn,
None really, other than the fact that it might be that you are using an arrow heavier than you need and may be losing some velocity that you would otherwise have . Yes, we are talking release aids only."
I guess I'm still not convinced that too heavy a spine is an issue from a well tuned bow when using a release and a drop away rest.
FL, I hear ya, and for what it's worth I'm leaning towards GT 7595, but right now I'm having no problems with the 5575 hunters. I'm confident I'll blow through any deer, but the hunters are only .006", and I want to get straighter arrows, so I'm putting alot of thought into my decision. Side affect of being a cheap fish excrement
Per Bob Ragsdale: "What are the ill effects of OVERSPINE with a really "straight ahead" launch?
Dear Glenn,
None really, other than the fact that it might be that you are using an arrow heavier than you need and may be losing some velocity that you would otherwise have . Yes, we are talking release aids only."
I guess I'm still not convinced that too heavy a spine is an issue from a well tuned bow when using a release and a drop away rest.
FL, I hear ya, and for what it's worth I'm leaning towards GT 7595, but right now I'm having no problems with the 5575 hunters. I'm confident I'll blow through any deer, but the hunters are only .006", and I want to get straighter arrows, so I'm putting alot of thought into my decision. Side affect of being a cheap fish excrement
09-20-2002, 01:27 PM
#13
Fork Horn
Join Date: Feb 2003
Location: Klamath Falls, Or
Posts: 300
RE: Too Stiff a spine theory exploration
I don't know why it reacts left. I am just reporting what I have seen. It seems to agree with the Easton tuning guide reaction for a stiff shaft. They aslo say show a stiff reaction to be point left.
Andrew
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Andrew
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09-20-2002, 02:00 PM
#14
Nontypical Buck
Join Date: Feb 2003
Location: CT, USA
Posts: 3,058
RE: Too Stiff a spine theory exploration
I think you also have to remember that just becuase you have a bullet hole it doen't mean your arrow flight is perfect...it's only perfect at where you shot through the paper.
A fall away rest can even be a hindrance on some single cam bows with poor nock travel,as ther eis no "cushion" as the arrow is forced down towards the shelf and then pulled back up. Some of the singlecam designs need the rest to help guide the arrow flight. this is why they often tune best with slightly stiff arrow.
Now to your choice in shafts...Try the Carbon Express Terminator Selects size 60/75. The black finish is 10.7 grains per inch, and the Camo is 12 grains per inch. Straightness is .003 (over a 28" span and they spin just about as straight as my CX 3D Selects which are rated at .001 per 28"
and weight tolerance is +/- 1 grain. They are available at CX dealers only. I've been quite impressed with them. Nicest all carbon shafts I've seen in a long, long time. First carbon shaft besides A/C/C's I'd consider hnting with in a long time. Prices are decent as well.
A fall away rest can even be a hindrance on some single cam bows with poor nock travel,as ther eis no "cushion" as the arrow is forced down towards the shelf and then pulled back up. Some of the singlecam designs need the rest to help guide the arrow flight. this is why they often tune best with slightly stiff arrow.
Now to your choice in shafts...Try the Carbon Express Terminator Selects size 60/75. The black finish is 10.7 grains per inch, and the Camo is 12 grains per inch. Straightness is .003 (over a 28" span and they spin just about as straight as my CX 3D Selects which are rated at .001 per 28"
and weight tolerance is +/- 1 grain. They are available at CX dealers only. I've been quite impressed with them. Nicest all carbon shafts I've seen in a long, long time. First carbon shaft besides A/C/C's I'd consider hnting with in a long time. Prices are decent as well.
09-20-2002, 02:57 PM
#15
Nontypical Buck
Thread Starter
Join Date: Feb 2003
Location:
Posts: 2,994
RE: Too Stiff a spine theory exploration
Jeff, perhaps I'm just lucky, but I get the bullet no matter what the distance past 5' is...
Thanks for the heads up on the selects. I'll definitely give them a looksee. The weight is in the right range, if I decide to go that heavy.
Lancaster Archery has them for $55 a dozen! Wow. Price is definitely right.
Jeff, can't tell from the site and gametracker doesn't list the terminator select, I assume these are internal component shafts? What nock do they accept? Thanks.
Edited by - Rangeball on 09/20/2002 16:05:30
Thanks for the heads up on the selects. I'll definitely give them a looksee. The weight is in the right range, if I decide to go that heavy.
Lancaster Archery has them for $55 a dozen! Wow. Price is definitely right.
Jeff, can't tell from the site and gametracker doesn't list the terminator select, I assume these are internal component shafts? What nock do they accept? Thanks.
Edited by - Rangeball on 09/20/2002 16:05:30
09-20-2002, 04:25 PM
#16
Nontypical Buck
Join Date: Feb 2003
Location: CT, USA
Posts: 3,058
RE: Too Stiff a spine theory exploration
<font face='Century Gothic'></font id='Century Gothic'>
RB,
Oh I don't mean to imply it wasn't possible, just be aware a bullet hole at one distance does not neccessarily mean one, elsewhere.
Now listen CAREFULLY <img src=icon_smile_big.gif border=0 align=middle>
The TERMINATOR and the TERMINATOR SELECT are NOT the same. Generally ONLY the Pro-shops will carry the SELECT model. The Standard Terminator (the $55 ones) are .006 with no weight guarantee..they are not nearly as consistent, and I do not really reccomend them other than for durability..MAKE SURE you get the Terminator SELECT, OK? <img src=icon_smile_big.gif border=0 align=middle>
JeffB
RB,
Oh I don't mean to imply it wasn't possible, just be aware a bullet hole at one distance does not neccessarily mean one, elsewhere.
Now listen CAREFULLY <img src=icon_smile_big.gif border=0 align=middle>
The TERMINATOR and the TERMINATOR SELECT are NOT the same. Generally ONLY the Pro-shops will carry the SELECT model. The Standard Terminator (the $55 ones) are .006 with no weight guarantee..they are not nearly as consistent, and I do not really reccomend them other than for durability..MAKE SURE you get the Terminator SELECT, OK? <img src=icon_smile_big.gif border=0 align=middle>
JeffB
09-20-2002, 05:11 PM
#17
Giant Nontypical
Join Date: Feb 2003
Location: HENDERSON KY USA
Posts: 6,634
RE: Too Stiff a spine theory exploration
Rangeball,
My bow has been tuned on a machine and has been laser tuned.I can put a stiff arrow on the bow and get a bad tear.I can put a properly spined arrow on the bow and get a perfect tear.The person that had it on the machine could not get the stiff arrow to react properly to the bow.As soon as the proper spined arrow was shot,the paper was perfect.
I don't have my bow tuned to an arrow.I have an arrow matched to my perfectly tuned bow.It shoots paper from the end of my 18" stabilizer all the way out to 10 yards perfect.By perfect I mean a slightly and I do mean very slight high left tear and by 3 yards the arrow is shooting bullet holes.
Easton's web site tries to explain some of the things that you aren't understanding.Go there and read their tuning guide.
My bow has been tuned on a machine and has been laser tuned.I can put a stiff arrow on the bow and get a bad tear.I can put a properly spined arrow on the bow and get a perfect tear.The person that had it on the machine could not get the stiff arrow to react properly to the bow.As soon as the proper spined arrow was shot,the paper was perfect.
I don't have my bow tuned to an arrow.I have an arrow matched to my perfectly tuned bow.It shoots paper from the end of my 18" stabilizer all the way out to 10 yards perfect.By perfect I mean a slightly and I do mean very slight high left tear and by 3 yards the arrow is shooting bullet holes.
Easton's web site tries to explain some of the things that you aren't understanding.Go there and read their tuning guide.
09-20-2002, 06:28 PM
#18
Fork Horn
Join Date: Feb 2003
Location: Klamath Falls, Or
Posts: 300
RE: Too Stiff a spine theory exploration
once again TFOX is giving great advice. You are going about it backwards if you art trying to tune a bow to an arrow. Always do it the other way around.
Andrew
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Andrew
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09-23-2002, 07:30 AM
#19
Join Date: Feb 2003
Location: Miami FL USA
Posts: 208
RE: Too Stiff a spine theory exploration
I agree that you should try to get the arrow to as close as you can to match the bows setup. However, don't be afraid to move the limb bolts tuning the bow to the arrows. That is one of the greatest advantages of a compound bow over a traditional setup.
Aim Hard!
Aim Hard!
09-23-2002, 07:53 AM
#20
Join Date: Feb 2003
Location: Chesapeake VA USA
Posts: 135
RE: Too Stiff a spine theory exploration
I agree with FLHunter -- Make the best approximate arrow selection you can for your set-up, then tune the bow to the arrow. A 1/2 turn on you limb bolts is very easy to do and with minor adjustments on those bolts, you can dial that arrow right in more effectivley than trying to find different lenghts and tip weights. No need to "have to shoot 65#" or whatever. If 63 works better, so be it.