arrow spine conversion...

[Russ Clagett]

Can someone tell me how to figure out what various spines in carbon arrows convert to in wood?

For example, a 500 spine carbon equals what in douglas fir..?

assuming tip weight and length are the same....is there a chart somewhere?

thanks!

[lpcjon2]

Your better off listing what poundage your bow is at your draw weight and we can figure the wood spine from that. That is the easiest way to do it.

[stringstretcher]

Convert ATSM spine to AMO spine by dividing by .825.  That will give you the actual AMO deflection

If you take the number 26 and divide it by the bow poundage, that will give you the exact AMO deflection you are looking for as a start

IE:  26 divided by 50 lbs=.520 deflection using amo standards

[WESTBROOK]

Your better off listing what poundage your bow is at your draw weight and we can figure the wood spine from that. That is the easiest way to do it

X2

Carbon and wood are soooo different there is no easy direct spine conversion.

Eric

[Fletcher]

Russ, I've not been able to figure out a good cross for carbon to wood.  Working with the Stu Miller program might help.  Best for me has been to just start over.

[NoCams]

Russ,
Like Fletcher said.... "Best for me has been to just start over. "

With that being said use Stu's calculator to get you close within reason and then buy the test kit from Surewood for your Doug Firs. Then cut them all to your normal length with your normal tip weight and bareshaft. Get the kit that has 4 spine groups in it and one will fly the best for you. Get two spines below and two above what the calculator tells you is the correct spine. Best $$$ you will ever spend and no more guessing about spines. Very handy tool to have, especially if you are a bow trader ! JMHO

[Russ Clagett]

That's what I thought.......was trying to figure out why I couldnt make sense out of it either....

I shoot 65-70 doug firs now out of a firefly longbow, but I've got another longbow coming....

The bow's owner shoot carbons that spine at 500 out of it, and I was trying to figure out what that means in doug fir language......

I'll try Stu's program, been pretty close in the past...

thanks!

[Swamp Yankee]

In my opinion comparing wood to carbon shafts is apples and oranges in how they perform dymanically, but the chart above does the math and should be a pretty good starting point to work with.

[Fletcher]

A set of test arrows as suggested by is a great investment for a wood arrow shooter.  Formulas for figuring spine work OK and will get you close, but the variables between the shooter, bow, arrow length, point weight, etc, make the formula a swag at best.  With the test arrows you will know in minutes exactly what spine you need.

With wood arrows, be careful with bareshafting.  Bareshafts tend to fly sideways and can crack or break when hitting the target crooked.  I recommend paper tuning.  It works just as well, better for many, and your arrows will last a lot longer.  I fletch my test arrows shorter than my regulars so they don't correct as quickly.