arrow weight tolerances - in practice

[gtek]

While Rick's article does contain a fair bit of pseudo-science and outright misstatement (especially the bits about aluminum arrows) the fact is spine is as important as he says it is.

I have carried out extensive studies that boil down to this- as little as 0.38 mm spine variation (about the thickness of two standard 40-pound A4 copier paper sheets) either between shafts in a group, or in spine-around-shaft reading of an individual shaft, can cost two points in a 12-arrow Olympic Round. This is a fraction of the variation one sees with certain brands of shafts including some recently introduced- some of which vary as much as 1.52 mm and more.

By way of comparison, the allowed maximum variation in Easton A/C/E, X10, and X10 ProTour for both static and SAS readings is less than 0.127 mm- a tolerance that is laser checked not less than four times and at least twice by hand on a master gauge on each and every single one of the above mentioned arrow shafts during fabrication of the individual shaft.

[Desert Archer]

Originally Posted by gtek

...spine is as important as he says it is.

Is that good enough moo-mop or do you want to question his credentials too?

...a tolerance that is laser checked not less than four times and at least twice by hand on a master gauge on each and every single one of the above mentioned arrow shafts during fabrication of the individual shaft.

Which may explain my un-scientific observation that my ACEs shoot better than any other arrow I've tried, even if I have no "data" to prove it. (smile)

Dave

[moo-mop]

Originally Posted by Desert Archer

Is that good enough moo-mop or do you want to question his credentials too?

I never said spine wasn't important, just that you could not say it was more or less important than weight or straightness. I've said this twice now . [Edit: this is not about credentials, this about whether there is data to back up claims, in science you shouldn't have to rely on credentials]

So I do need data for this; but I totally understand why we don't have such data, it's privileged market info. Desert archer - i'd be interested in why you believe weight is less important than spine? Would you be happy if all the companies decreased their weight tolerances in order to increase spine tolerance (yes I know they probably don't trade off like this)?

What gtek and rick say if I read correctly is all/most manufactures have good enough weight tolerances, not all have good enough spine tolerances - am I correct?

They say they have done tests, I believe they have. I've done tests too but not as many or as thoroughly - it's not my job , [edit: not only this: they only apply to the arrows I have used so I couldn't publish them even if they were thorough enough].

I guess what we have learnt is that these arrows, if within tolerances both are probably not holding the likes of me, a hobby archer, back due to weight or spine... and that was the question after all.

I can model weight loosing me a less than a point for my set-up [edit: over 6doz at 70m]. I can't model spine, but I have done an experiment that does suggest further spine matching [floating in baths etc] - the exp does happen to be with ACEs - is not as vital as has been claimed by others [edit: for my level of shooting] (as with weight matching and filing bits of points etc).