Translating Carbon Spine to Wood Spine/ Help

[PastorSteveHill]

Hi guys. Could someone translate this arrow to a wood spine please:

I shoot Beman MFX Classic 500
From the nock groove to the bop it is 30.5
I have a wrap (8 gr) Feathers (14 gr.) and a nock (9 gr) on it.
150 gr. field tip. + (14 gr. insert)

 

I would want the wood arrow to be about the same length 30.5 or 31' arrow.

What spine wood arrow would translate? With a 125 or 150 gr. point???

Thnks

[Jim Jackson]

Wood arrows are fickle and fun to try to figure out.  I don't think you will find a set answer to this question and therein lies the fun of the whole deal.  The point of choosing wood over man-made materials is in the challenge of the medium.      

[Stumpkiller]

http://www.beman.com/products/shaft-selector  

According to the Beman website your spine on those shafts would be 32 to 36 pounds.  Pretty willowy.  What is your draw weight at 28" (or where the bow is marked).  I would need a 340 for my draw - same as yours - 30-1/2" BOP for my bows in the 50 to 55# range.

But I don't know a carbon shaft from a fishing pole so you'd better wait for a gooder answer.

[Fletcher]

Steve, I've had pretty good luck crossing alum over to wood, but I've not figured out carbons.  I'd probably have to shoot them and I have no real desire to do that.

[Paul Mattson]

Do Not! even try matching.  It's not going to work.  I can give you the spine,but to many other variables.

[WESTBROOK]

You'll have better luck just matching wood to the bow spec. Carbon and wood are 2 different animals and they dont speak the same language.

Eric

[Flying Dutchman]

There is a simple conversion technique that everybody should know.... Underneath you find a short overview of the most common values:
CARBON -----> -----> -----> -----> -----> WOOD
15-35 or 0.600” becomes: 26/0.6 x 1.2115 =  52.5 lbs
35-55 or 0.500” becomes: 26/0.5 x 1.2115 =  63 lbs
55-75 or 0.400” becomes: 26/0.4 x 1.2115 =  78 lbs
75-95 or 0.300” becomes: 26/0.3 x 1.2115 = 105 lbs

It is really simple to calculate: devide 26 inch by the deflection, i.e. 0,400 and mutliply it with 1,2115. That's all!

What it all makes pretty confusing is that carbon knows two notations: AMO, like 15-35 and/or deflection, 0.600 in this case.
But the AMO notation of 15-35 has nothing to do with the AMO for wood. As you can see that is in this case 52,5

[PastorSteveHill]

I'm shooting a Fox Royal Crown
48 lbs. @ 28, I draw 29 inches. I assume it is 51 at my draw.

I dont know for certain but I also assume it is not cut to center.

So would a 30 inch arrow spined at 50-54 work?

[Bjorn]

The riser is about an eighth from center-looks like to me. You will need a 30" shaft with your draw, if you are using a non Dacron string 55/60 would be a starting point. Get a test kit and have a look at Stu's Calc which might help narrow it down. Consider your tip weight too, if it is going to be over 125.

[PastorSteveHill]

I use Stu's calculator for carbon, but don't understand the wood section???

[Bjorn]

Steve,  I can't help you with Stu's Calc-only mentioned it because folks seem to like and use it. Here's what I do: bow weight, add 5# for FF type string, add 5# for each inch over 28", add 5# for each 25 gn over 125gn, add 5# for center cut. I bareshaft to check-you can skip this part if you want. This formula works and will get you close, get shafts above and below your result from the formula to test, quirks in shooting style can create variances.

[Flying Dutchman]

Originally posted by PastorSteveHill:
I'm shooting a Fox Royal Crown
48 lbs. @ 28, I draw 29 inches. I assume it is 51 at my draw.

I dont know for certain but I also assume it is not cut to center.

So would a 30 inch arrow spined at 50-54 work?

we need to know more things:
- how many strands is your string and is it FF?
- what is the weight of your point/BH?
- what kind of feathers do you use?
- do you use a wrap/cresting?
- What kind of wood do you use?

But the answer of Bjorn will get you close too!
I would say that 50-55 is too low.56-60 might be a better choice.

[MO Bow]

Just to give you an idea, I shoot a recurve 52# at 28".  I use 30.5" arrows spined at 70# exactly.  I could go lighter on the spine and use a shorter arrow, but I like a longer arrow.

You might be pretty close to that number.  Dependong on how you shoot, you might be closer to the 60-65 range.

Adam

[Flying Dutchman]

Here is another idea: I shoot a Cari-bow Peregrine. It is a hybrid longbow which is plain wicked fast. At 9 gpp it shoots around the 195 fps.

The bow is 45lbs@29". My drawlength is 29 to 29,5 inches and there is a 10 stands FF string on the bow.The bow is, together with the strikeplate, + 1/16" cut perhaps a tiny bit less, so very close to center-cut.

I use a 11/32 wooden arrow of 53 lbs exactly.
Length (BOP to nock groove) is 29,5 inches
Point: 100 grains
Feathers: 3 pcs of 4 inch, helical
Standard plastic nock
I use a four layers crersting on the end of the shaft which will add appr. 20 to 25 grains.

My arrrows fly like darts!

[metsastaja]

You can use Stu's calculator for wood arrows.
Select wood shaft. You then need to fill in the boxes below. AMO static spine, Shaft Grains per inch and shaft diameter.

Using FD's info I ran Stu's Calculator
 

[ny state land]

What Flying Dutchman said, if you Add about 8-10 pounds to your draw weight it will get you close. You can go on the high side then tune it out with heavier heads until they bare shaft correctly. In the above pics Les is showing a 100 grain point so with a heavier head you would require more spine.

[Flying Dutchman]

Very close Les    :