Greetings & Merry Christmas...Need a bit of advice....If I am shooting 500 carbon arrows and they fly perfectly, what spine wood would be comparable to the 500 carbons ??? Thanks & be safe !!! Des

I just ran 3 or 4 flavors of .500s across my wood arrow tester, and they all read #57.5….

But that’s why they make test kits…

Depends on the length and tip weight. Something like a 50-55 probably at 29" with 125 tips, maybe 55-60.

A .500 carbon if it is actually .500 deflection is equivalent to .412 in a wood shaft using standard wood shaft spine measurement methods. That's 63lbs.. But the shaft diameter is going to need to be figured in the equation as well.

fdp - could you expand on that (.500 carbon equivalent to .412 wood), please? Is that the 28" vs 26" shaft length difference, or something else inherent in the measurement protocols?

Maybe all shaft types should just go back to pounds: 63 lbs is 63 lbs! :)

Synthetic starting is measured over a 28" span using a 1.94lb. weight. Wood shafts are most typically measured I've a 26" span using a 2lb. weight. So yes it is the difference Inn the span length and weight used.

So, to convert the carbon .500 measurement to the wood equivalent you multiply The .500 by .825. 500 x.825 =.412.

But #63 in a 26” arrow is not #63 in a 30” arrow, so either way, you still have to do some figgerin’….

Then to get the numerical weight

26÷412 = 63lbs.

Arrow length has no bearing on static spine but it does on dynamic spine. Using the regular old 5lbs. per inch rule works pretty well for carbon or aluminum shafts too.

Borax measuring over a 26" span using a 2lb. weight hives you the spine for a 28" arrow.

Good enough.

'Borax' sorry about that spell check didn't like Corax I guess. :)

Thanks fdp!

It doesn't matter what the material is. Deflection is deflection which makes spine spine.

If the carbons aren't actually the spine they are advertised at, or aren't at least in the same standard spine group as woods can be had in they are essentially over priced junk.

Riverwolf:

What Frank is saying is correct. The problem is there are two standards being used, the AMO and ATA. The latter is meaningless, the former is based on a mathematical formula.

Using the AMO formula, if you divided the deflection in thousands of an inch into 26 it will give you bow weight for a 28"arrow, i.e. .500 into 26= 52#.

Bob

Since this post started, I decided to do some investigating on the subject.

I have several old Easton spine charts from different periods of time. Their charts say the italicized number it the most of often used shaft for the arrow length. both of the charts I used were for hunting arrows 28" long using 125gr. points. Chart #1 1916 shaft for use in recurve bow 35-39# Chart #2 1916 " " " 29-34#

#1 2016 " " " 45-49# #2 2016 " " " 34-39#

#1 2114 " " " 50-54# #2 2114 " " " 39-44#

#1 2117 " " " 56-60# #2 2117 " " " 49-54#

#1 2216 " " " 61-65# #2 2216 " " " 54-59# All shafts are XX75 alloy. No wonder there is so much confusion. Easton archery are the ones that petitioned the ATA to change the spine standard. example using the AMO standard a 2117 same length, point weight and alloy spines 81# & a 1916= 53#

This is ridicules!!!!

Bob

Sorry I made this so confusing...No harm intended...Here's the skinny.....54" Shrew L'il Favorite...Velcro shelf & side plate...49lbs @ 28".....Arrows 27" 500 Easton Axis....draw length 26.5....150 up front not including a 16 grain aluminum insert...3 4" feathers....Split finger... Thought about trying wood but just asking for opinions on spine....Thanks for all the info & Merry Christmas...Des CHRIST IS BORN !!!!!!

Desperado- You did not make this confusing, it always has been. They issues is that there are many, many variables and mathematics is not very good at dealing with that.

So what we have to do is limit the variables, target style or hunting style, shaft material. draw length, get some experienced comment, reject some of that, and do some trial and arrow.

What we can offer is some experienced comment. But you still have decide who do you trust.

So, good short answer? There ain't none.

But wait! If you have reasonably normal draw weight, shaft length, draw length, point weight and bow weight,,,,,, you might try some 55 to 59 spine. Leave them full length to start and have at least three point weights on hand to begin tuning. Maybe four.

Also have several different kinds of tabs on hand.

This is what keeps archery fascinating over many years. - lbg

The question wasn't confusing to me at all. You simply asked what wood arrow spine will have the same static spine measurement as a .500 spine carbon. The answer is simple.

You spent all that time and energy typing out all those numbers and then spelled “ridiculous” wrong. Bless your heart.

Very interesting thread.

I spelled wooden wrong in the title.....:( :( Duh !!!!!

“Using the AMO formula, if you divided the deflection in thousands of an inch into 26 it will give you bow weight for a 28"arrow, i.e. .500 into 26= 52#.”

What’s kind of funny to me… Speaking of “YMMV“ scenarios…

How long are my arrows? Just about 28 inches.

What’s my actual net poundage at my draw length? #52

What spine am I shooting? 500 . . . . . . . . . . . .

With 200 grain points.

Ah, well…. I’ll just blame it on the footings.

;)

Corax_latrans:

Your question is easily answered; using the amo standard for every inch longer than 28" the dynamic spine decreases 5# and vis/versa for shorter, increasing by 5#/inch, however if your using carbon shafts they use ATA standard which is 1.94# weight at 28" centers. That is where the confusion starts.

Bob

Your draw weight is around 45# and a 27” 500 carbon with only 150 up front=way overspined IME

So 45/50 wood cut to 27” bop with 125 or more up front should be good to go for you…..

One thing that saved me a lot of time and headaches was to buy a test kit from 3 Rivers. I had them cut to 29" and had 125 grain tips glued on. I believe their kit covers 4 spine groups and you can choose between a couple of ranges. This helps me figure out very quickly which spine group shoots best from whichever bow I choose.

I guess I’m not tracking with the idea of four different arrows mines and only one weight for the points. Especially if you are set on using a specific length, I would think that you would want to have a few more options in order to make everything come out exactly where you want it…

But I guess it just comes down to how fine you want to cut it… As I mentioned to Frank earlier in an aside, it’s kind of like choosing between buying your shirts in size small/medium/large versus ordering by neck size, sleeve length, and full vs trim vs athletic cut…. You can wear either one to the dance, but it will look a lot sharper if you have all of the dimensions and the overall fit dialed in for your personal physique.

I find an arrow that is the lengthbthat I want it, within the spine range that it needs to be for draw weight of the bow and the point weight I want to use and tune the bow to shoot it. Easy Peasey.

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