I've been told (and rightfully so) that I was overspined on my setup when I based that spine on a spinechart. Most agree that the charts overspine you.Could someone make a REAL spine chart to use?Or recommend one?

Check this out; www.arrowskp.com

Easton charts are notoriously over-spined.

Jim,Thanks! I'm really looking for carbon arrow spine,is there a way to convert one of the other spine charts?

A lot about spine depends on how close to center shot the bow is also.

I still use a spine chart from the 70’s for my aluminum shafts. It’s a start. Carbons are another animal. Got to look close as to what 500 spine as example to poundage. Is it 35-55 or is it 30-50? No standards for shafts manufacturers.

Charts are only correct for machine people, been that way forever. Bait for fools..

Charts are only correct for machine people, been that way forever. Bait for fools..

Charts are only correct for machine people, been that way forever. Bait for fools..

You can have two people with the same draw and the shooting the same bow and there's probably more than a 50/50 shot of them requiring two different spines, at least different dynamic spine.

Bowmania

razorhunter, spine is easy as long as you have a basic understanding of how it's measured, and what it means.

There are 2 different methods of measuring arrow spine, both of which are based on deflection, or how much the arrow bends.

Carbon and aluminum are measured on what are known as ASTM parameters. That means that the arrow is supported cross a 28" span, a 1.94lb. weight is hung in the middle, and the deflection is measured thousandths of an inch. For instance a carbon arrow that has a measurement of .500.

Wooden arrows are measured using what is known as ATA spine parameters. That means that the arrow is supported across a 26" span with a 2lb. weight hung in the middle, and the deflection is measured. For instance a wooden arrow that has a deflection of .500.

Once you know the deflection measurement, then you need to convert that deflection measurement into pounds. To do that you divide the length of the span into the deflection number. So, the carbon arrow as an example. 28 divided by .500 + 56lbs. Using ASTM parameters, that is the pounds of spine for that arrow.

Now, the wooden arrow. Rememeber the span is 26". So 26 divided by .500 = 52lbs.

Here is where the difference between the 2 measurements comes in to play, and it is based on the difference in the span, and the weight used.

To convert the ASTM (carbon and aluminum) spine to ATA (wood spine) you have to multiply the ASTM number by .825. Our .500 example for ASTM of .500 X .825 = .412 ATA. 26 divided by .412 = 63lbs.. That is where the trouble starts for folk when they start trying to match carbon arrows to recurves and longbows. In this example, if you chose the .500 carbon or aluminum, and thought it was going to be in the 50'ish lb. range, youare off by 10 pounds at least.

Then, as mentioned above, you have to consider the centershot measurement. And the measurement that the factory gives is meaningless for most people. The important measurement is the way the bow is set up to shoot. If the bow is cut to center, and then you add 1/8" of material to the sight window, it now 1/8" BEFORE center. This matters because every 1/16" cahnge in centershot either way changes the spine requirement of the bow about 1 spine group, or 5lbs..

Once you understand these things, and it really isn't as complicated as it sounds when you read this, spine is really not difficult. You measure the draw weight of the bow, and buy arrows that match the spine requirement.

Personally, I convert all carbon or aluminum spine measurements to ATA because I grew up with it, I understand it, and makes matching arrows to bows very easy for me.

You do still have to add spine for heavier points/broadheads, orextra length, as well as decrease spine for arrows shorter than 28". As well as for low stretch string material.

Keep in mind also that your individual shooting quirks will have a certain amount of influence on the final spine requirement as well.

jk and Bowmania,I understand that things will need to be tweaked,but a starting point would be helpful. Maybeeven a program that allowed you to input numbers and it give you a range.

fdp,I may could decode what you've said,but at the moment I'm one confused puppy,lol

Fdp, that was a really concise explaination.

I know the only real way to learn is from experience. However, a head start is a great help. If a person basically gets told what spine is probably correct then they can play with it through tuning which teaches to me spine and changes possible through options. Through bareshafting and the changes you make you can see the effect on spine. When someone is completely new to trad it is intimidating sometimes if you're someone who wants to put the effort in to get the best setup and learn the most possible. The spine charts are off but new folks have no idea. So they start with the wrong spine and the changes they think they need to make aren't tuning their set and can't necessarily figure it out. Others simply go for it. That is why so many people shoot overspined. I'm sure I'm not the only one to belong to some Face book trad groups. Someone will ask for spine advice and get responses like a 340 on a 48# bow. Now I don't know their exact setup but I don't think I need to. I think razorhunter should state his specifics and get a head start. Then study, experiment, and learn. That headstart would be no different than a spine chart that actually worked.

Charts are at best a guideline.Better to buy one of the test kit's with several spines to try.

http://www.taylortel.net/~rickbarb/dynamic_spine_calculator.html

That is the link to Stu Miller's latest dynamic spine calculator, that I have working online.

It has a few bugs, but is very accurate as long as it is fed accurate entries. At the very least it will get you into the correct spine shaft, then you can work with that shaft from there.

Rick

What fdp said is perfect!

As already said sometimes different folks use different spines. Your fingers only straighten out so far and people are different. The more the string has to go around your fingers the weaker spine you'll need because your arrows will flex more than some others. So a chart for all finger shooters would be impossible.

Yes, Frank has the correct explanation. Many folks error on the stiff side, they have for as long as I can remember. But then you get bows that defy all logic, like my two duo shooters, 3/8" out side of center. If a chart is set up considering center shot, an 11/32" arrow is 11/64" off center in a bow that the string is the center of the bow. If that starting point for wood is correct, then I would need to drop 30 pounds in spine . The reality with both of these bows is that the best spines are those that match a pure center shot bow with wood arrows. If one was really new at this but had those original instructions that work very nicely for the average recurve, they could very likely shoot themselves in the bow hand with first shot if they had bows that are far off center like a self bow or one of my duo shooters. this reminds of that perfect yew billet bow that I got to shoot. I was made before WWII, had just a little bit of set was 7/8" across at the arrow shelf. It drew in the mid 50 pound range at my draw, was as fast my 50 pound laminated longbow and it shot the same 50- 55s with 160 grain heads. There is just no way that bow could handle more than a 10 pound spine adjustment downward. My wife's 40 pound spine arrow would not fly out of it at all, i was lucky the arrow stayed in one piece. There must be some additional math that needs to come into play with certain stats and exceptions.

Have you seen this one: http://web.archive.org/web/20071229024852/www.arrowsbykelly.com/Spine_Charts.html

It's not so much that i'm trying to find an arrow for a particular bow right now, and I could probably get pretty close if I were, I'm just talking about a starting point for someone who doesn't have a clue where to begin. For instance, if I were asked what spine i needed for a 35#@28" bow, there would be a pretty strong opinion shared by most of what that spine should be. Yes, it would have to be tweaked, but you could offer a starting point, especially after asking a few questions such as what draw length the person has and what point weight they want to use and what length they are trying for.. just a simple chart for a starting point. But I haven't checked out Rick's link yet, it sounds like exactly what i'm looking for

razorhunter, as I stated, it really isn't that confusing in practice. And in order to be a complete archer and have a reasonable chance of being a relatively good shot you have to understand spine. And it doesn't matter if you are shooting an all natural materials bow, a recurve, a longbow, or the latest and greatest compound.

There are also other factors that come in to play eespecially with carbon arrows.

1st., there is no such thing as an arrow that has a deflection that fits in for instance the 35-55lb. range. That's ludicrious for arrow manufactureres to even try and sell archers on that fact. But they do. The only way that can be possible is in bows that have a huge amount of centershot adjustment, by cutting the arrow to various lengths,or by manipulating point weight. In this context, you can do the same thing with wooden arrows if you so desire. You COULD successfully tune a 75lb. spine arrow to a 55lb. draw recurve by leaving it long enough, and/or adding enough weight to the front end.

2nd. Carbon arrows are notoriously inconcictent in spine from one batch to the next, and particularly from one maker to the next.

Forget charts and test kits. Call Lancaster describe your goals and ask.

By the way, arrow length and draw length are important factors...this ain't rocket science...not a numbers game.

jk...it IS a numbers game. Lancaster is not going to do anything (and I love the folks at Lancaster) but get you in the same ballpark that you can get in all by yourself, if you understand spine, and the things that affect it dynamically.

They have no idea of the personal tarits that are affecting the dynamic spine of a shot anymore than we do when we make suggestions on threads like this. And yes, Lancaster does it based it based on numbers as well. There isn't any other way to do it.

Bowmania, sent you a PM. I can't always tell when my go through.

He could just ask here and get closer than he probably is.

I started typing earlier and then finished a few minutes ago, so the post went in "earlier" than it should have... but i'll just it again now..

" It's not so much that i'm trying to find an arrow for a particular bow right now, and I could probably get pretty close if I were, I'm just talking about a starting point for someone who doesn't have a clue where to begin. For instance, if I were asked what spine i needed for a 35#@28" bow, there would be a pretty strong opinion shared by most of what that spine should be. Yes, it would have to be tweaked, but you could offer a starting point, especially after asking a few questions such as what draw length the person has and what point weight they want to use and what length they are trying for.. just a simple chart for a starting point. But I haven't checked out Rick's link yet, it sounds like exactly what i'm looking for"

Here is one from the link I posted:

For a 28"OAL arrow at 35lbs. draw weight, with 125gr. head, standard Dacron string you would want an arrow with a deflection of around .760 based on ATA. That would be a .900 in ASTM.

Way back when Easton made many different arrow sizes, we use to split the difference between a 1920 and a 2018, or a 2016 to a 1918. with more available consistent spines, we could stick to a an arrow length and not need to jump through hoops to get a good flying arrow. The carbons? In comparison it is an OR situation, operators responsibility. We sell you the stiff carbon straw, you figure it out for yourself. With wood, I buy two dozen 55- 60s, I separate the 55s to 57s for one head weight for one bow and the 58s to the 60s for another bow. that idea works until I get the next dozen and the whole works spines at 56 to 57 pound spine and doesn't weigh within a ten grain span, but 4 grain span. Surewood can match shaft weights to prior orders. Now if wood arrow shaft suppliers, could go to spines that didn't start and end on 5 pound increments, but perhaps spine across that 5 pound marker say 53-57s, we could get really finicky with it. One thing that does irk me a little. I have a set of tapered carbons, cut to my length. They did not fly out of the intended bow, but are perfect out of another, no reasonable messing with point weights could change it. Now that same bow will shoot a wide variety of wood arrows and so will the one that the carbons were intended for. Two bows will equally shoot the same variety woodies, but only the one bow will shoot the carbons. Maybe carbons are not as sensitive out of pure center shot bows.

Me, I think archery has room for both athletes and geeks, both.

One side is into numbers, the other is more into physical stuff.

I guess I just will never figure out all this spine stuff. Way to much information for this pea brain. I shoot several different bows all about the same draw weight (42- 46#) and carbon arrows. I use the 35/55 arrows and select the point weight I want to use and cut the arrow down a little at a time until it bareshaft well. According to all this technical stuff I am way over spined, and for that matter so is everyone I shoot with. If my arrows don’t hit where I’m aiming I don’t blame it on spine, I also have a question for you gurus. Doesn’t point weight affect spine?

I don't know why guys have so many problems with carbon arrows. I suppose it's because they start with a shaft that's too stiff to begin with. The manufacturers don't help either with there arbitrary spine numbers like 35-55s or CX 150-250 etc.

I can simplify things for a lot of archers by listing actual spines for common carbons. Most .500 spine shafts will spine between 63-65#, as will CX 150s.

Most .600 shafts spine between 52-55# making them particularly useful since many shoot lower weight bows.

I recently bought some CX Heritage 75s, which are supposed to be .670, and they spine right at 45#. They fly perfectly out of a 45# recurve at my 27" draw as will 600s cut slightly longer with the heavier BHs that I hunt with.

I can't shoot .400s as they're much to stiff for my present bows, but I still have some that I used to use when I shot heavier. They seem to be less consistent in spine (maybe because they're older) but they seem to come in at 72-80#, that's a couple different brands.

Bet thing I ever did was buy a spine tester so I know where I'm starting from and also to compare arrows to something that shoots well out of a bow I'm using.Hope this helps.

Frank...of course point weight affects spine as does overall shaft length etc..

"You COULD successfully tune a 75lb. spine arrow to a 55lb. draw recurve by leaving it long enough, and/or adding enough weight to the front end."

Dale: "Most .600 shafts spine between 52-55# making them particularly useful since many shoot lower weight bows."

I find that #600 Easton Axis, which are more consistent near #600 than competition, spine close to #600. I have noticed that "spine testers" vary wildly from one to the next..so I trust Easton (but not their charts).

Spine = deflection, not bow weight (not "52-55").

JK, I don't know what you're trying to say other than you think the Axis shafts are more consistent. I have a Don Adams spine tester which spines w a 2# weight on 26" centers and a .600 spine shaft will indeed spine or "deflect" to indicate that it will work for a 52-55# bow.

I think it's a more realistic standard than Easton's 1.94# weight on 28" centers. It also compares more readily to wood spines.

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