Easton shafts & points - quality control?

Senlac

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Cold wet day, so I set to making up a load of new ACEs. And boy, what a surprise I got. Is this normal?

First, the ACE shafts. I've got 24 brand new ACE 670 C3 shafts (should last a year or more), in two new tubes straight from Easton, all cut (by Quicks' saw) from the same end to exactly the same length. Initial weighings, straight from the tube, were all a bit different, so I cleaned the internal ends to get rid of any saw residue, and gave the inside a blast of compressed air to flush out any dust etc. Then I weighed them again carefully. My grain scales read to 0.1 grains, but the repeatability is around 0.3grn - so I weighed every shaft five times (in random order), all balancing on exactly the same point, and averaged the readings.
The result was a big surprise. I was expecting all their weights to be be very close, maybe +/- 0.3 grains or so. But....
- the first dozen ranged from 164.3grn to 166.0grn (range of 1.8grn i.e. 1.1%!!!)
- the second dozen ranged from 164.2grn to 165.6grn (range of 1.4grn i.e. 0.9%!!!)
Remember these are not only all 670s, but are all C3s - i.e. they've been selected by Easton to be close to identical. But I'm seeing 1% variation in weight. That's a lot! Can it be that Easton's quality control on ACE shafts specifies a 1% weight range as "identical"?

Second, Easton points. I got 14 brand new 100 grain break-off points here - plus 11 old (used, but cleaned) ones. I weighed them all as per the procedure I used for the shafts.
The result was a another surprise. Again I was expecting all their weights to be be very close, maybe +/- 0.3 grains or so (and the used ones to have a wider range). But....
- the first 14 (new ones) ranged from 99.3grn to 100.2grn (range of 1.0grn i.e. 1.0%!!!)
- the second 11 (used ones) ranged from 99.2grn to 100.0grn (range of 0.9grn i.e. 0.9%!!!)
Can it be that Easton's quality control on break-off points also specifies a 1% weight range as "identical: As for the old (used) ones: interesting how they've been worn out a bit - but the variation is the same.

Perhaps I'm being too picky... But as I'm building new arrows I would like them to end up all within a weight spread of 0.5grn or so. My current competition set meets this spec (well, the best 7 do, the other three are outliers). And I wasn't as careful building them.

Perhaps my weighing method is flawed in some way and actually they're really all the same weight...

I heard that the top guys get a bucket load of arrows from their sponsors and select from them. I.e. pick the most identical 12 and use them. Maybe I'm seeing the reason they do this......
 

wingate_52

Active member
The weight difference in the points is acceptable. I file mine so they are all the same. I use mine full length, and i doubt any consistency if people break off the shafts. I built my own arrow saw and hold and rotate the shaft. Then after weighing the cleaned shafts, wire collet brush and meths, weigh the shafts then trim the cut end on another jig with a diamond plate perpendicular to the shaft, rotating the shaft on supported bearings, until I get all the shafts to the same weight. It all goes to pot using hot glue on the points. The arrow set completed are within 2 grains.
 
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RichParker

New member
According to Easton the weight tolerance is +/- .5 gn so your findings seem to be a little high.
I normally weigh eveything them find the best matches for shaft and points e.g. if the shaft is .5gn under fit a point that is .5gn over or as close as I can get.
 
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Senlac

Supporter
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DHBowman: FYI a 10grain difference in total arrow weight can cause a vertical separation of 2ft or more at 80+ yards. A year's shooting of ACEs or similar can rub off this much weight. So best to (a) start with arrows that weight pretty much the same; (b) rotate your arrows so they all wear out at about the same rate; and (c ) weigh them occasionally to check how they're doing.
 

Senlac

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RichParker: thanks very much for the Easton spec - I wasn't aware of it. Looks optimistic. Re "I normally weigh eveything them find the best matches for shaft and points e.g. if the shaft is .5gn under fit a point that is .5gn over or as close as I can get" - thks. That's what I did this evening: I matched each shaft to a point so that the original 24 ACEs ended up in two packs of 12, each pack having total weights (after points & nock pins, before vanes) all within a spread of about 0.5grn. The FOC points may be fractionally different, but at least the weights are well grouped now.
 

Rik

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Interesting.
I looked back through my notes on the last set of ACE 670s (also c3s) I weighed.
I use a reloading balance which reads to 0.1 grns, and appears to be consistently repeatable to that.

The nominally 100 grain points came up as 99.4 to 99.7 - 0.3 range. No real variation.
The uncut shafts weighed between 176.7 and 177.4 (total range 0.7). Same after cutting.
After cleaning and glueing, it was down to 0.5 grains across the set.
That's a variation of about 0.2%.

Admittedly, this was in 2009, so there's always a chance of a lapse in qc since then...
but I'm a little concerned about "14 new points" - it sounds like they didn't come out of one packet, in which case I would guess they would be less likely to be consistent.

Basically YMMV. Could it be your scales are worse than you thought...?
(And yes, I know I'm a bit anal with the weighing thing, especially since after 6 months of shooting, unless you're very careful about rotating them, the range will have opened up considerably).

An adjustment of 0.5 grains to a 100 grain point would alter the FOC by what? 0.5mm? Less? Probably not measurable.
 

Senlac

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Thanks Rik, really helpful. Yes, I'm not confident in my scales' accuracy (i.e. repeatability, let alone absolute accuracy). I can see my 5x measurements of each one did show up consistent differences... but maybe the quantum of the differences still isn't reliable. Yes, maybe Easton's qc standard has eased-off. BTW the 14 new points were one packet of 12 plus 2 extras (I was told) and the variation seems to be not just in two of them. Either way, there's not much I can do about it except match-up lighter points with heavier shafts to keep the all-up weight distribution tight to around 0.5grn spread. And yes, I agree this is all a bit anal and the changes that inevitably happen after a load of shots. I discovered this after a season's shooting when I'd naively used shafts nos 1-6 a lot more than nos 6+: up to 10grn differences. But my philosophy is "Lock-in all the technical variables. Then you know it can only be you..."
I'll be beating-up my remaining 620s by reserving them for the endless blank/blind boss practice, tweaking the bow tune for the 670s, and holding back on these new 670s for scoring rounds. That will minimise wear and damage. Perhaps with one lot for club rounds and the others for competitions. Also I'll have enough to spot any outliers - and put them aside. Maybe tweak their nock positions to see if that brings them in (my shooting's not yet good enough to spot the ACE eccentricity differences via trial nock rotations tests - I've tried that and my current variability is greater then the effect I'm trying to measure. Feels like physics again, shades of Heisenberg)
 

jantar77

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DHBowman: FYI a 10grain difference in total arrow weight can cause a vertical separation of 2ft or more at 80+ yards.
It is hard to belive to me that 10grain difference can cause 2ft separation especially because I tested it with very experienced archer. (my consistency is not trustworthy enough :) He took two sets of ACEs with 100 and 120 grain points to see which of them groups better and (to some of my surprise) they were vertically in identical height @70m. And you're talking about 1 grain difference. I don't mind if someone is too picky about his/her equipment but I wouldn't suggest to weight your arrows down to 1 grain makes sense unless you are that good that your sponsor will send you a bucket.
 

Senlac

Supporter
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I admit I've not tried it. But I got this advice from a couple of UK Level 4 coaches at the UK Archery training centre at Lilleshall "7 grains difference = 2 colours at 80-90m". And yesterday I reality-tested it with an Olympic archer who said a 10 grain arrow weight was a lot and could easily lead to this sort of spread at Olympic distances
 

Senlac

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Hi Munsterman. Thanks very much for pointing me in the direction of the Bow Intl. article. It's certainly helpful - especially as I thought the "C3" batch label on ACEs was about spine. Now I know spines of ACEs are, according to Easton, v. close and the "C3" is about weight. Also the article confirms that Easton weight tolerance in a "C3" batch is +/-0.5 grains for a new tube of shafts - which I take as meaning a tube of new ACEs could have weights over a 1 grain range (and 1.5 grains range for C3s from different tubes).
My 670s still seem to have a bigger weight range though.... May be my scales, but I think not. I've now made up the arrows and, by careful mixing and matching of points and shafts and pin nocks I've ended up with sets of 12 arrows all within a 0.7 grain spread. Yes, over-doing it. But best to start in the right place and re-weigh & re-sort occasionally as they wear down?
 

Rik

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All very well measuring and sorting components but how do you control the amount of glue used?
How much do you think glue weighs? Try looking at the volume of (for example) 0.5 grains of hotmelt...
 

Senlac

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All very well measuring and sorting components but how do you control the amount of glue used?
I guess this boils down to two things?
a) If your shooting philosophy is to do what's necessary to make the arrow spread from your kit much less than arrow spread from your technique (and so there's no uncertainty as to whether poor scores are your kit or your technique), then you'll want to reduce the arrow spread due to weight variations to a certain level. And if so, then.......
b) What's your acceptable level of arrow weight variation? On this, I've checked my Lilleshall notes and confirm I was told there that "7 grains = 2 colours at 70m". I.e. 1 grain = 3.5cm. Separately, though the first link says it's irrelevant, the second link in joetaply's really helpful post from earlier today contains a mathematical calculation of 1 grain = 2cm at 70m. Not a wildly different result from the 3.5cm. So if, say, you shoot at Bowman level you might want to make sure the variation in your arrows' weights result in less than one colour spread, then as one colour = 12.2cm you'll may be able to accept arrow weight variations of 4-6 grains. If you're a MB or GMB you'll be wanting rather tighter variation in arrow position due to their weight differences?
However, as it's actually not very difficult to build a set of arrows that are all within 1 grain of each other, why not do so? Yes, they'll wear down a bit and the weight range of the set will likely increase - but you can weigh them occasionally and try to keep your 6 competition arrows within grain or so of each other.
So.... as to the "... amount of glue.." question. It does't really matter as it's very little and as long as your glueing technique is pretty constant it will be within the 1 grain tolerance that's already better than really necessary. Either way, having gone through the whole arrow construction process, weight them and then chose the 6 that are closest to each other?
 

joetapley

New member
However, as it's actually not very difficult to build a set of arrows that are all within 1 grain of each other, why not do so?
That's pretty much the answer are regards weight. It's never a bad idea to build your own arrows as you can weigh the individual components. You do occasional get a (weight) rogue component.

With Carbon arrows the important arrow property, as regards grouping, is not weight but "spine" (stiffness characteristics). The only cheap way to test arrows is to shoot them bare shaft at a distance compatible with you skill level and check the grouping. The only tool to "adjust" spine is nock rotation which can sometimes move a flier towards the main group. It's from the bare shaft grouping that you select the six (or more) competition set not from the arrow weight distribution.

(there is a chapter on this topic in The Heretic Archer if you can beg, borrow or steal a copy )
and trumpet blowing http://www.tap46home.plus.com/mechanics/arsel.htm
 

Senlac

Supporter
Supporter
Hi again Joe. Thanks very much (to others too) for all your help on this topic. It's been extraordinarily helpful in clarifying things.
Yes, you make a very good point about spine. I've spent a lot of time homing-in on the right spine - but I've not thought of looking for spine outliers within an Easton tube batch.
I had thought a lot about, and done various trials to find, whether any of my existing fletched arrows were outliers. But this was about the construction of ACEs leading to the carbon coating on the shafts being asymmetric and so each arrow having a favoured nock orientation. My conclusion from those tests was that my shooting was not tight enough and repeatable enough to identify this reliably. But, as I said, this was all about asymmetry - not about different spines.
Now you've said there could be variations in spine within a tube set - and that the tests to spot this and correct it are the same as for asymmetry. I.e. try rotating the nock. I'll believe you - thanks for the insight! As it happens I have here six un-fletched but otherwise fully made up and weight-matched ACE 670s. So earlier today I shot them again and again (12 or so times) at 40 yards. I'm sorry to say I couldn't see any consistent pattern in outliers. The reason was I was tired and sore and my shooting was c**p. Or maybe this is inevitable at a handicap of high 30s? So I'll probably give up and fletch them.

Which brings me to another thought - which might be a worthy topic for a new post...
I've been pondering on my progress through the gents recurve classifications / down the handicaps, and what mattered at each point. Here's a very crude summary, just to illustrate what I'm rambling about - and to get your reactions (all below is for Senior Gents)...
Handicap >58 (chasing 3rd): bow and technique basics; club bow's fine; aluminium arrows
3rd = 58
Handicap 58->50 (chasing 2nd): getting used to 60yds; best to have your own bow - or rental; aluminium arrows are fine; clicker & rods optional; mostly about kit
2nd = 50
Handicap 50->44 (chasing 1st): getting used to 80yds; carbon arrows necessary; clicker & rods necessary; still a lot about kit, and can still get away with sloppy technique
1st = 44
Handicap 44->36 (chasing BM): getting used to 100yds; spinners recommended; no longer about well-tuned kit (that's assumed) - good technique now critical
BM = 36
Handicap 36->28 (chasing MB): handling county tournaments; no longer a hobby - becoming full-time; arrow spine & weights important; increasingly about mental?
MB = 28
Handicap 28->22 (chasing GMB): handling international tournaments?; no longer part-time - a full-time job; arrow spine & weights critical; 95% mental game now; ??? What else? You tell me!
GMB = 22
 

joetapley

New member
What's missing from your list is the word "decent coaching". You can get to Bowman/MB with good planning and hard work as an individual (though decent coaching should facilitate this process). To reach elite level though a think you need decent coaching.
 
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