Carbon Arrow Selection & Research Guide | Chapter 3 | Read the Arrow Safety Bulletin |
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ARROW STRAIGHTNESS SELLS ![]() HOW TO THEY MEASURE THAT? Before we get too deep into this topic, it's worth noting that there doesn't seem to be an accepted universal method for HOW arrow straightness is measured. Per ATA/ASTM standards, arrow straightness should be measured along the full length of the shaft minus two inches. But as we understand it, this is NOT how things actually go inside the industry. On a number of occasions, we have heard arrow companies accuse each other of cheating their straightness measurements - either by measuring only short sections of their arrows, or by obtaining their straightness numbers via undisclosed measurement methodologies. Every arrow manufacturer is absolutely sure their numbers are accurate and their competitors' numbers are fabricated. If you think the bow business is cut-throat, you should witness how the arrow companies go at it behind closed doors. To avoid being shanked at the next trade show, we'll stay neutral and assume that everyone's' arrow straightness numbers are reasonably honest. But just be advised, there are certainly some cowboys in this market. A tolerance of +/-.001" is good work for a CNC mill on aluminum alloy. The idea that a piece of thin flexible tubing can hold that tolerance along a full 28"+ length is, well, quite fantastic. ![]() CUT FROM THE SAME CLOTH` The difference in a +/-.006" shaft and a +/-.001" shaft is more razor-thin than you might think. Today, most carbon arrow shafts are constructed by taking very thin layers of carbon sheets and rolling them up into perfectly straight tubes (usually 6ft. long or so), much like you might roll-up a big map. The layers are wound around a metal mandrel, then the carbon tubes are heat-treated to bond all the layers together. When the heating process is complete and the carbon tubes cool down to room temperature, they are cut into sections (raw shafts). Some of the shafts, particularly those that come from the center of the roll, retain their ±.001" straightness while other sections distort slightly from the heating/cooling process. As we understand it, the results vary from run to run and day to day. In most cases, even the manufacturer doesn't know how the day's crop of shafts will come out. But once the shafts are made, the manufacturer measures the straightness of each shaft section and sorts them accordingly for banding and sale. One sort may be named and marketed as one arrow, another sort as something else. For example, the Beman Bowhunter +/-.006" and the Beman ICS Hunter +/-.003" are just two different sorts of the same shaft - same raw materials - same construction technique - different wrapper. Same is true for the popular Gold Tip Hunter ±.006", Gold Tip Hunter XT ±.003", and the Gold Tip Pro ±.001" shafts. They're not different arrow shafts. They're just different cuts of the same raw product. ![]() |
DOES ARROW STRAIGHTNESS MATTER? OF COURSE IT DOES` From a pure physics standpoint, yes! Arrow straightness certainly does matter. We all remember how a bent aluminum arrow fishtailed and corkscrewed wildly. Yes! Straighter arrows undeniably fly more accurately. In long-range laboratory conditions with a mechanical shooting machine, the straightest arrows with the best spine consistencies will always group best. But try to keep this issue in reasonable perspective. You are not a mechanical shooting machine. You don't shoot in laboratory conditions, and you probably don't shoot at extreme distances (100+ yards). The straightness difference in a +/-.006" arrow and a +/-.001" arrow is mathematically minuscule. We're not talking about the kind of distortion you would see in a bowed 2x4 at Home Depot. We're talking about tiny hair widths. So we have to admit, the real world benefit of a +/-.001" arrow probably has more to do with selling arrows than shooting arrows. The truth is, only a handful of the world's archers actually have enough shooting skill to truly differentiate between a very good +/-.003" arrow and a "pro grade" +/-.001" arrow. And within the typical bowhunting range, any difference would be practically imperceptible. Nonetheless, bowhunters tend to attribute their successes or failures to their equipment rather than to their actual skills. So owning and shooting a set of professional grade +/-.001" arrows may provide some bowhunters with an edge in confidence, even if the actual technical advantage is negligible. If you're one of the many archers who believe that success is only one more purchase away, buy whatever arrows you like. Just remember that super-straight arrows won't correct poor shooting form. In the end, the benefits of a good practice regimen and proper bow tuning will FAR outweigh the benefits of shooting expensive arrow shafts. But don't tell the arrow companies we said that. ![]() SPINE CONSISTENCY PROBABLY MATTERS MORE` Remember how we mentioned the cut-throat squabble about arrow straightness? Well, the same is true for spine consistency, and this spec is sometimes discussed as a matter of manufacturing tolerance. So we'll mention it here. If you test for spine deflection while slowly rotating the arrow, the spine deflection should remain constant. No matter which direction you bend the shaft, it should be equally resistant at all points, right? Nope! The wound layers of a carbon arrow will often have a seam somewhere inside the circle (unless the shaft is filament wound). This seam creates an imbalance in the spine consistency of the arrow, such that the arrow is a bit more stiff at one point around the circle. It's unfortunate, but the process by which carbon arrows are manufactured inevitably results in some imperfections. And if you want to get really technical, most arrow shafts aren't even perfectly round for that matter. But the important question is, does it really make a difference? From a pure physics standpoint, yes. But again, few shooters have enough skill to notice small variations. For the weekend bowhunter and backyard enthusiast the issue is largely inconsequential. But that doesn't stop the arrow companies from bickering about who has the best spine consistency and accusing each other of spine crimes. After all, every arrow company wants YOU to believe that their arrows will give you a technical advantage, even if that's a little distortion of the truth. Again, we'll avoid the internal melee here by not pointing fingers, but if you wish to know more about spine variance, check the forums. There are a few forum regulars out there who own spine testing devices and Hooter Shooters. And they'll be happy to disagree with us on this issue. Despite the debate, consumers remain surprisingly blasé about spine consistency, and most manufacturers struggle to make technical hay about their spine consistency specs. Most buyers are just fixated on straightness. |
ARROW DIAMETER MADNESS ![]() |
Carbon Arrow Selection & Research Guide | Chapter 3 |
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