Finding the spine of an arrow
 

I just bought another dozen shafts and I really want to make these a very close set. I bought a digital grain scale and have weighed each shaft. Out of a dozen, there were only two arrows that were 2 grains heavier. Not bad for Gold Tip XT's.

Anyway, I also want to find the spine of each arrow and fletch them accordingly. I've read about floating them and other gizmos that can be made to do this. Tonight, I had a thought and wanted to check it. I pulled the nock out of an arrow and using a flashlight, you can definitely see a seem inside the shaft. Would this be the spine or stiffest part of a shaft?

Maybe I am going way overboard with this stuff (can you say addiction?) but I've read enough about this sort of thing and how it really does make a difference. So, I thought I've give it a shot with this dozen.

Any insight on this"?

RE: Finding the spine of an arrow
 

I'm convinced it makes a big difference, and least on arrows that tend to be inconsistant in specs (most qualify here). The only good way I know to do it, is to use a spine tester (fairly cheap to make one). You could always resort to turning nocks to get best groups, and cull arrows that you can't bring into the group. This would be a time consuming task requiring accurate shooting, but should end up working quite well.

I can't comment on the floating-in-water method. I've never tried it. It doesn't sound like it would be very accurate.

RE: Finding the spine of an arrow
 

I have been thinking about this lately too. Some one recently wrote an article of putting arrows in a spine tester and spining them to find the stiff side. I did this with my cheetahs and there was 1/1000 difference around the shaft. I also did it with ICS Camo hunters and about the same difference. Perhaps these arrows don't overlap?

RE: Finding the spine of an arrow
 

MUZZYMAN88, Even though an arrow can check very semetrical on a spine tester. In most cases there is one spot on that arrow that preforms the best. Nock tuning is the best way that I know of to find that spot. I shoot with(but cant compete with) guys that shoot 300 with 50+ Xs and during a shoot I see them rotating a nock just because the arrow isnt hitting the X in the middle of the X ring. Must be terrible to shoot like that ha ha. GGBH

RE: Finding the spine of an arrow
 

What I'm curious to know here, is what exactly we are trying to find here. Is it this "seam" that is created from the construction of the shafts? If this is the case, I think I just found it on the Gold Tips. Inside the arrow, you can definitely notice a seam if you use a flash light.

I am under the impression that it is the seam, which in theory is the heavier part of the each shaft and should be the part that goes bottom down if you float them in water.

I don't know, I'm grabbing at straws here, but I want to get a better understanding of this.

RE: Finding the spine of an arrow
 

Muzzyman88, I use a spine tester to check the spine around the arrow. I'll put the arrow in the tester and spin it, when I start I call this 12oclock: say it reads .340 I'll spin it and watch the dail indicator and read it again at 3 oclock: .348 same at 6 oclock: .346 and 9 oclock .339. Do that to the whole dz and keep track of spine. Some people indcate the spine on the stiffest side and some the weakest. I indicate mine to the .340 side of the arrow(I shoot c@c feather up) the idea behind this is when I release the arrow with the same spine indicated to the c@c feather my arrow will bend the same for each arrow thus giving me a more consistant release and flight. When they float then in the tub they say the heavy part of the arrow will spin to the bottom and you would mark it there. I'm not very good at explaning things so I hope you understood.

RE: Finding the spine of an arrow
 

Sjb3 What arrows do you do this with. I have carbon techs and bemans, and both of mine the run out is about 1/1000 maybe 2 to be generous. Just wanting to know if these are points going down the tube.

RE: Finding the spine of an arrow
 

Ewolf, the new Beman Max 4 and the Black Max are some of the best arrows I have checked for spine. I was really impressed with these shafts. Gold tips were the worst, the spine was very inconsistant. I can't remember right off but some were out .030-.040. I've also read that a few other people that check spine had the same readings. I checked out 4 dz GT hunter pros @ over $90 a dz and was not impressed. I also heard that CarbonTech had about the best spine tolerances,but never purchased any. For the price I can get Bemans for Its hard to buy anything else>

RE: Finding the spine of an arrow
 

From what I've seen, that's incredible for carbon arrows. I've never checked carbon techs, but I've never seen any carbon - aside from ACC's - with that little variation. The ones I've checked (Beman, GoldTip, PSE, Arrow Dynamics... to name a few) all had spine variances averaging between .010 and .020" on the same shaft (some even worse - much worse), and up to .050" variance from stiffest to weakest in a dozen.

I swear this is the truth, believe it or not, my cedar arrows were straighter and more consistent in spine than the carbons I was working with. But it's been a couple of years now since I went back to aluminum and quit beating my head against the wall with carbons. Maybe they've improved?

Sorry, muzzyman, but even though I did a lot of spine testing on carbons, I never looked inside them to try and match spine readings to a seam. Never thought to even look at that, since I thought they all had a bias wrap inside. That kind of construction wouldn't show a straight seam.

RE: Finding the spine of an arrow
 

I have checked 5-6 dz of the new Bemans some Max 4 and some Black Max arrwos and the worst out of these were .011. and one dz I checked were Max 4 340 and they were all within .004 or better.

RE: Finding the spine of an arrow
 

Arthur I did me some testing.:D I have bemans from 5-6 years ago. I found them and checked them through the spine tester. HOLY CRAP. From spining the shaft I got .011, .012, .011, .014, .011, .023, .024, .018, .24. Nothing close to that with the newer shafts. It will be amazing what we will be at in another 5 years.

RE: Finding the spine of an arrow
 

I'm gratified to hear they've actually made some improvements in spine consistency, ewolf! Question: Did you just check once on each arrow, or did you spin each arrow and check them all at several points around the shaft? Last time I fiddled with them, I could get spine variances up to .015 or more on the same shaft. Going from the stiffest point on one shaft to the limpest point on another, it wasn't suprizing to get a variance of .040 or more within a dozen new shafts. Much, much worse after they'd been used on the range for a month or two.

There is certainly a desperate need for continued improvement, but it will only come if archers demand it. Even then, I doubt we'll be amazed. They'll still be selling their factory seconds - the ones that are just good enough to not go in the scrap bin - as cheap 'hunter' grade shafts and there'll still be tons of people who can't shoot good enough to see them for the junk they are. Then it'll still be a step higher up the price scale for the ones that are almost right, and they'll still be charging astronomical prices for the shafts that actually do come off the mandrel the way they intended.

RE: Finding the spine of an arrow
 

Arthur the numbers I provided are the variation from spining them while in the spine meter. The new ones are alot better than the old ones thats for sure.

RE: Finding the spine of an arrow
 

That has not been my experience with Bemans. The ones I tested were much worse. When checking aluminum arrows, I'd get at least .003 to .004 difference on a dozen. None of the carbons I've tested have been anywhere near as consistant. For them to test better than aluminums seems unlikely at this point in their development.

RE: Finding the spine of an arrow
 

CarbonTech

Got my Cheetah 3D's.....

Whoa

RE: Finding the spine of an arrow
 

I'm just a rookie at this, but I've found the same thing that Jeff B mentioned. Carbon Tech seems to be much closer in shaft to shaft spine, and spine around the shaft than the other carbons I have. I got .002 spine around the shaft and .004 as the greatest variation within the dozen shafts, and that was with Cheetah Hunters (.006). Other all carbons varied by .014 in the half dozen I tested. Still, the results with ACCs made me question my construction of the spine meter, and the purchase of other arrows to try. The ACCs were .001 around the shaft, and only varied .001 within a dozen. They seem to shoot more consistently, but It's hard to tell at my skill level.;)

I'll have to check for the seam like you mentioned, and compare it with the spine around the shaft to see if there is a connection, but I'd guess there probably is.

RE: Finding the spine of an arrow
 

And thats what you pay for , some of the JUNK carbon cost almost as much and won't group worth a darn , and thats with field tips , let alone fixed broad heads .
I'm pissed they took my matrix arrows off of the market . Basically an acc with a larger diameter .