Black Frog

Sorry guys that I've been away for quite a while. Band and work schedule has been through the roof the past 3-4 months (and just got back from a week of playing in Sturgis ..... )

Some may remember that I finally got a nice spine tester completed earlier in the year: http://forum.hunting.net/asppg/tm.asp?m=979296&mpage=1&key=spine%2Ctester

Some people had asked me to check back with spine values as I get shafts in for fletching up arrows. Well I'm making up some new hunting arrows for a friend and myself and thought I'd report what I found this week.

My friend wanted to stick with all-carbon arrows and bought a dozen of the Easton C2 Carbon Epic 400's. I prefer ACC's and bought a dozen of the 3-49's for this upcoming elk and deer season.

I put all the raw shafts on my spine tester, and also on my grain scale. As shafts are rotated on the spine tester, you'll see a bit of wobble on the indicator dial from your hand pressure while turing the shaft, depending on how "dead on" you are over the support bearing. You can get a good average of spine deflection once you play with it a bit- you get fairly consistent in you spinning pretty quickly. It's not that hard to notice when a shaft comes along that has an obvious spine wobble.

First the C2's. They advertise 2.0grains across a dozen. Following weights are RAW shafts with NO nocks in them.

Spine: Weight:
.402 262.0
.401 261.8
.408 258.6
.390 259.6
.407 258.6
.396 259.5
.388 260.7
.397 260.1
.388 261.2
.390 260.1
.403 261.2
.400 262.7

Spine span of .020" and a weight span of 4.1grains. One shaft had a noticeable spine wobble of over .007" as it was turned with the weight on it. Doesn't make their advertised spec of 2.0 grains across the dozen. I'll leave it up to my friend if he wants to return them or not.

No onto my ACC's.

They advertise 0.5 grains across a dozen- that's a tough spec to meet and I'm not sure if I've ever seen a dozen from ANY manufacturer meet that spec from the factory without some personalized "hand-sorting".... Following weights are shafts with ACC nock inserts installed from the factory.

Spine: Weight:
.375 291.0
.374 291.4
.373 290.9
.376 291.1
.373 291.1
.371 291.6
.373 291.6
.371 291.8
.374 291.2
.375 290.9
.372 291.5
.376 291.0

Spine span of .005" (pretty nice!) and a weight span of 0.9 grains (not bad...) This kind of shows why the ACC's are consistently such an accurate arrow. Even though this batch didn't quite meet its spec of 0.5 grains for the dozen, it's not far off. I did notice one shaft had a wobble of almost .005" in spine as I rotated it on the tester. That shaft is getting weeded out immediately....

I love my ACC's year after year......

P.S. Is Rangeball still around here? Did he ever finally cave in and buy a hanging bow scale? I thought I'd guilt him into it eventually.

JeffB

Todd...excellent info...

Surprised me a bit about the spine variance in those epics...thats a bit high for Easton C2 construction based on my experience...

but they do fall within spec for weight...they are +/- 2 grains (4 grains variance total)

A/C/Cs were no surprise of course..

BTW...make sure the INSIDE of the shafts are clean too..that can add a grain here and there..

Black Frog

[] Duh. Geez, I've been out of it for a while! You are most definitely right. They do say +/-2 grains per dozen. My mistake. [8D]

Just so everyone who reads this thread knows that the Epics are advertised 4 grains (+/-2) across a dozen, and the ACC's are advertised 1 grain (+/-0.5). I mistated those specs in my first post. In my case, both sets of shafts met their weight specs!

I do take a "bore weazel" and some barrel patches and run them down the inside of the shafts. Some people would be surprised at how much crap comes out on that patch!

You can never be too anal about your arrow shafts.....

JeffB

I agree...and that just sounds sooooooooo wrong

Straightarrow

Black frog, was your spine test, for the range on a dozen, or was it the maximum difference between the stiff side and weak side of the worst arrow in the dozen?

From what I can tell from my spine testing, aluminums and aluminum/carbon arrows don't need to be spine tested. Putting the cock fletch on the stiff side, when it's only .001-.003 difference, doesn't make a noticable difference for me. All-carbon arrows are a different story, expecially the lower-end ones. I've measured as much as .085 variation on some dozens. I've even seen single arrows with the stiff side being .030 stiffer than the weak side. I need to test more brands, since I've yet to come across an all carbon arrow, where the spine tests don't make you cringe. The ones you tested appear to be much better than any I've checked.

On the positive side, I've gotten amazingly good flight off even these poor arrows, by culling a few of the worst and then aligning cock feathers on the stiff side. Then, if the spine is close to weak for my bow, I turn my bow poundage down so they all shoot on the stiff side. In the two years that I've been doing this, my broadhead groups have shrunk dramatically.

Black Frog

SA-

My readings were average deflection of each shaft as it was rotated. I noted that the max wobble within a shaft (difference from weak side to stiff side) for the Epics was over .007", and the max wobble for the ACC's was almost .005". Only a couple of shafts had noticeable wobbles to them of more than a .003-.004". Not too bad

I always cut off from both ends when assembling new arrows. Seems that you'll mostly find the runout variances on towards the factory ends.
Yup, that's why I built my tester in the first place. I don't believe too many marketing claims until I can prove it to myself! Some spine toleraces on some arrows are pretty scarey.

JeffB

If you are going to shoot all carbons, the Carbon Techs are tough to beat..the only thing they lack IMO is durability compared to Goldtips or an ST AXIS. Spine, straightness, weight across a dozen, and from dozen to dozen is the best I have seen.

PABowhntr

I just love it when you guys really get into the tech. sideof things. Arrow construction is one of my favorites. The results aren't entirely surprising. I wonder what type of finding you would have had with some less expensive ICS style carbons....such as the Goldtip Hunters or Easton Excels.

Thanks for the info Todd. Nice to see you back. You and I need to discuss some of my new binos when you get a chance.

JeffB

Same thing as on the really expensive Goldtip Pros

ijimmy

Thanks for the info , confirming what many have counted on here , acc quality . A guy gave me some c2s , looks like thats about what they are worth .

I wounder what satilte shafts will do , they say they are THE all carbon arrow .