information for people that spine check arrows

[enewman]

https://1drv.ms/b/s!AtVqxLy9AZcGhHrSN3QVAFROPOvU

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Good info!

[Rat]

Looks like the analog is the closer of the two, makes sense with the weight of the digital.

I would guess the other option, besides travel and weight, would be the tolerance of the spine selection at the factory.

There has to be some shafts that come in between .300 and .340, say .330. Do these get packaged and sold to big box stores or does the selection criteria for a given spine include these shafts as well?

For example, let's say an arrow manufacturer has model sin the .240, .300 and .340; does this mean that:
A .240 is really between a ..210 and a .260
A .300 is really between a .260 and .320
A .340 is really between a .320 and a .360

Or maybe the manufacturing is precise enough that the swing wouldn't be that large...

Just like straightness tolerances, manufacturers should also give the spine tolerances of their arrows.

[enewman]

Originally Posted by Rat

Looks like the analog is the closer of the two, makes sense with the weight of the digital.

I would guess the other option, besides travel and weight, would be the tolerance of the spine selection at the factory.

There has to be some shafts that come in between .300 and .340, say .330. Do these get packaged and sold to big box stores or does the selection criteria for a given spine include these shafts as well?

For example, let's say an arrow manufacturer has model sin the .240, .300 and .340; does this mean that:
A .240 is really between a ..210 and a .260
A .300 is really between a .260 and .320
A .340 is really between a .320 and a .360

Or maybe the manufacturing is precise enough that the swing wouldn't be that large...

Just like straightness tolerances, manufacturers should also give the spine tolerances of their arrows.

Gold tip tolerance is +/-.020. Element and blackeagle are +/-010. Easton not saying yet. Takes time for then to respond. I need to call dorge and see what his arrows are.

Now most manufactures spine sort. So if they are a +/-010 arrow. You may buy one set and be in the .300 next set might be .290 and third set .310. This is why some people notice they have to retune when buying new arrows even if same ones.

Now in the set. I don’t know. Person ally I don’t like seeing more then .005 difference but that is a pipe dream.

[enewman]

https://1drv.ms/x/s!AtVqxLy9AZcGg19HE8PtiHMK4biS


black eagles this set has a .014 spread

[enewman]

https://1drv.ms/x/s!AtVqxLy9AZcGg2LOJIHunwICVpA6


Easton .004 spread. much better arrow

[Rat]

Originally Posted by enewman

Now most manufactures spine sort. So if they are a +/-010 arrow. You may buy one set and be in the .300 next set might be .290 and third set .310. This is why some people notice they have to retune when buying new arrows even if same ones. ..

Really? I don't see .010 making enough difference to retune, maybe if you are on the bubble of being under spined to begin with.

I shot in two different arrows this weekend: Gold Tip Velocity @ .300 and Black Eagle Carnivores @ .340. The only change was the arrow, both have 100 gr brass inserts, same everything. Bow was tuned with the Gold Tip Velocity shafts, fall away rest, etc.

The Carnivores shot just a tad tail high at 20 yards when bare shafting; and keep in mind they are a slightly smaller OD than the Velocity shafts.

@ 20 yards the broadhead POI was MAYBE 1/2-3/4" low, well within my shooting ability margin of error anyway.

My assumption was that the tail high was due to the smaller diameter of the shaft. Maybe I am wrong, but if spine was that critical I tend to think it would have made a bigger difference.

In my experience, I have seen that an arrow will begin to need retuning when we hit the critical mark for a weak spine; then the arrow is all over the place. But stiff arrows seem to be fine, even REALLY stiff arrows. It is not uncommon to see competition arrows with big diameters being very stiff based on charts and ballistic profiles. Shooting a .150 Gold tip 30X, from a 60 lb bow, at 29" with maybe 200 gr upfront is wildly stiff, yet we see it all time on indoor rigs.

So, when we are running the stiff edge like this, is .040 really going to matter, or is it only when we are running the weak edge that we see the need to retune?

IDK, I'm just thinking out loud now...

[enewman]

Originally Posted by Rat

Really? I don't see .010 making enough difference to retune, maybe if you are on the bubble of being under spined to begin with.

I shot in two different arrows this weekend: Gold Tip Velocity @ .300 and Black Eagle Carnivores @ .340. The only change was the arrow, both have 100 gr brass inserts, same everything. Bow was tuned with the Gold Tip Velocity shafts, fall away rest, etc.

The Carnivores shot just a tad tail high at 20 yards when bare shafting; and keep in mind they are a slightly smaller OD than the Velocity shafts.

@ 20 yards the broadhead POI was MAYBE 1/2-3/4" low, well within my shooting ability margin of error anyway.

My assumption was that the tail high was due to the smaller diameter of the shaft. Maybe I am wrong, but if spine was that critical I tend to think it would have made a bigger difference.

In my experience, I have seen that an arrow will begin to need retuning when we hit the critical mark for a weak spine; then the arrow is all over the place. But stiff arrows seem to be fine, even REALLY stiff arrows. It is not uncommon to see competition arrows with big diameters being very stiff based on charts and ballistic profiles. Shooting a .150 Gold tip 30X, from a 60 lb bow, at 29" with maybe 200 gr upfront is wildly stiff, yet we see it all time on indoor rigs.

So, when we are running the stiff edge like this, is .040 really going to matter, or is it only when we are running the weak edge that we see the need to retune?

IDK, I'm just thinking out loud now...

Some of what I see I’m sure is due to the amount of tip weight. 250 to 300 gr. For a standard set up prolly not. I am looking at testing this. Just trying to find the same arrow with a wide spread. I had them in the fire and ice but I had to give them back after testing.

[Briar Friar]

Originally Posted by Rat

Looks like the analog is the closer of the two, makes sense with the weight of the digital.

I would guess the other option, besides travel and weight, would be the tolerance of the spine selection at the factory.

There has to be some shafts that come in between .300 and .340, say .330. Do these get packaged and sold to big box stores or does the selection criteria for a given spine include these shafts as well?

For example, let's say an arrow manufacturer has model sin the .240, .300 and .340; does this mean that:
A .240 is really between a ..210 and a .260
A .300 is really between a .260 and .320
A .340 is really between a .320 and a .360

Or maybe the manufacturing is precise enough that the swing wouldn't be that large...

Just like straightness tolerances, manufacturers should also give the spine tolerances of their arrows.

Well crap. Now I understand why Ive been told to shoot just one arrow.