Arrow making guide. Proper Arrows are Essential If you're one of the many bowhunters who select arrows each season by just grabbing a handful from the miscellaneous arrow bucket at the local super-mart, you may be surprised to learn that you've been cheating yourself. Shooting the proper arrows will greatly improve your accuracy and success in the field - and for less money than you might think. If you want reliable and accurate performance from your compound bow, your arrow must be specifically matched to YOUR bow setup. There is no such thing as a "one size fits all" arrow. An improperly sized and/or poorly constructed arrow will not only fly erratically, profoundly degrading your accuracy, but it may present a safety hazard for you and your expensive compound bow. If you are serious about bowhunting, you owe it to yourself (and the game you pursue) to shoot the right ammunition. Modern archery is a technical sport. So there are a number of technical considerations to juggle when selecting arrows: proper spine, FOC balance, weight, straightness, fletching material, fletching angle, arrow length, etc. And if you're feeling a bit lost, don't worry. This isn't exactly rocket-science - our selection guide will provide you with all the information you'll need to choose the right arrows for your bow. These next sections will take you step-by-step through the process of selecting and ordering custom carbon arrows for YOUR bow system. We hope you find this help section useful. Parts of an Arrow Let start with the basics. The foundation of every arrow is the SHAFT, a long hollow tube usually made of aluminium, wood or carbon/graphite composite materials. The rear of the arrow is fitted with a small piece of moulded plastic called a NOCK, which allows the arrow to physically attach to the bow's string. At the front of the arrow is a point (or pile) or, with carbon or aluminium arrows, a small aluminium (sometimes plastic) sleeve called an insert. The insert gets glued into the end of the shaft and provides a threaded hole in which to screw in the arrow's TIP. A tip doesn't necessarily have to be a practice point (as pictured here). A standard insert allows you to screw-in and use of a variety of tips in the same arrow (broadheads, judo-points, blunt-tips, field points, fishing tips, etc.). The last component is the arrow's FLETCHING. The arrow's fletching is usually done with colourful parabolic or shield shaped pieces of soft plastic (vanes) or feathers. In most cases, the three fletches are glued onto the shaft in an equally spaced circular pattern, with two fletches one colour (the hen-fletches) and the the third fletch a different colour (the cock-fletch – the one that faces away from the handle or riser of the bow). Standards of Measurement. The standard method of measuring an arrow is to find the distance between the bottom of the groove of the nock (where the string rests in the nock) to the end of the arrow, not including the tip or “pile”. Be advised that some archery shops, particularly the "bargain basement" type and many online stores may be unaware of industry standards. So don't trust anyone declared measurement of your arrows other that your own. If you are buying replacements for your existing arrows, be sure to MEASURE FOR YOURSELF before ordering custom carbon arrows. Once an arrow is cut, the process can't be undone. So as in carpentry, the measure twice and cut once philosophy must be observed. If you already have existing arrows which fit your bow properly, simply measure one by this method and order the same size. If you are unsure about what arrow length is appropriate for your bow setup, the next section may help. Measuring the Adjusted Draw Length of the Bow The proper length for your arrow will depend upon several factors: the draw length of the bow, the type of bow you have, and the type & position of your arrow rest. Before we dive into this issue, we should briefly discuss how the draw length of a bow is measured. Officially - according to the standard AMO method (Archery Manufacturers Organisation) - a bow's draw length setting can be found by measuring the distance between the groove of the nock - to a position 1 3/4" forward from the pivot point of the grip - when the bow is at full draw. Confused? Not to worry. There's a simplified method too. Conveniently enough, for most bows, 1 3/4" forward from the pivot point of the grip puts you roughly at the outer edge of the bow's riser. So without splitting too many hairs, we can say that a bow's draw length is approximately from the nock point to the front of the riser - when the bow is drawn back. So if you drew back a 29" arrow and the insert of the arrow lined-up with the front edge of the bow's riser, the bow is set for approximately 29" draw length. Whew! Glad that's covered! If you're truly an archery junkie, you may have also heard about the concept of True Draw Length, which is an older and much less popular method of measurement. Officially, True Draw Length is the distance at full draw from the nocking point to the low (pivot) point of the grip. So a True Draw Length measurement will be 1.75" short of an AMO draw length measurement. There isn't much talk about True Draw Length these days, and it's fine point of archery jargon that really isn't worth dissecting however, many field archers draw the arrow so far that the point or pile of the arrow is actually on the pivot point of the riser, a good inch and a half further drawn than most target archers. Also, we recommend you not automatically trust the factory sticker on your bow that indicates draw length. Measure for yourself. In many cases, the manufacturer's sticker and the ACTUAL draw length of the bow can be quite different - sometimes dramatically. And since changing your draw length may necessitate changing arrows too - we can avoid some trouble here by thinking ahead. If your bow does not already fit you comfortably, you should have the draw length adjusted before ordering your custom arrows. Arrows which may be perfect for a bow at 29" draw length may be totally inappropriate for the same bow set at 27" draw length (much more on this topic later). Measuring the Draw Length Requirement of the Archer. Obviously, the draw length setting of the bow and the required draw length of the shooter should match. If they don't, we have some work to do first before thinking about what arrows to select. Unlike a traditional recurve bow that can be drawn back to virtually any length, a compound bow will draw back only a specific distance before it "stops." Compound bows are designed to be shot from the full-draw position. If a compound bow is set for a 29" draw length, it should always be shot from the full 29" draw position. A bow that's set for 29" draw cannot drawn back to 30" or 31", without modifying the setup on the bow (or forcibly overdrawing the bow - a dangerous practice). Similarly, a compound bow should not be shot from a position less than full draw either. Where the bow stops, you stop. So if you're a 29" draw, then your bow should be a 29" draw. Easy enough! To measure your draw length, determine the length of your arm-span in inches. Stand with your arms out and palms facing forward. Don't stretch when measuring. Just stand naturally. Have someone else help you, and measure from the tip of one middle finger to the other. Then simply divide that number by 2.5. The quotient is your approximate draw length (in inches) for your body size. The majority of compound bow owners set their bows for too much draw length, which results in poor shooting form - inaccuracy - and painful string slap on the forearm. You will better enjoy - and be more successful with your compound bow when it is fitted properly to your body. And if in doubt, choose a little LESS draw length rather than a little more. If you've heard that longer draw length bows shoot faster, you heard right. But don't even think of shooting an excessively long draw length just for the sake of generating more speed. That's a very poor trade-off which you will regret. Shooting your bow at an overly long draw length won't make you more macho. It will just make you miss the target. So don't do it. Shoot the correct draw length. If you are a person of average proportions, your arm-span will be roughly equal to your height (in inches). So there is often a direct correlation between a person's height and their draw length as well. Once you have computed your draw length using the method above, you can double-check yourself by using the scale below - to see if your number is within the expected range. More Draw Length Discussion So, how close do you need to get? Within an inch? Half-inch? A quarter-inch? This issue could be debated, as there probably isn't a right and wrong answer to this question. For most shooters, a ±½" change in draw length is hardly noticed. To be realistic, half-inch sizes are probably precise enough (27½", 28", 28½, 29", 29½", etc.), particularly for the purposes of hunting and recreational archery. Besides, as your bow string ages and stretches over time (as ALL strings do), your draw length will slightly increase - a little fraction at a time. So constantly maintaining a razor-specific 28 13/16" draw length may be a frustrating endeavour for you and the pro-shop. If you're new to the sport, and unsure what draw length is appropriate for you, we strongly recommend you just play the averages and use the chart above. But admittedly, there is no perfect formula to solve this problem. Every shooter is different and the opinions on the methodology for measuring and checking draw length vary considerably throughout the industry: the yardstick against the breastbone, the fist against the wall, tip of the finger to the top of the shoulder, the arm-span method, etc. Without the benefit of an actual bow to draw back and actually check - each of these methods only provides us with an estimate. If your club has a drawstick (see image below) that will be more accurate but even then, you'll likely find that even the "pros" don't necessarily agree. If you go into several different archery shops to be measured for draw length, you're bound to get a variety of "expert" opinions. So before you get frustrated, remember that determining an individual's draw length isn't exactly a measurement of scientific certainty. So if you're just getting started in the sport, there's no need to get too carried away computing the square-root of your hypotenuse. Instead, we recommend you just play the averages and choose an initial draw length that's similar to others of your same size and stature (reference the chart above). There will always be time to "tweak" your draw length a little as you gain experience and learn to analyze your shooting form more closely. YOU will ultimately be the final judge on your own perfect personal draw length. Drawstick illustration. Chart to calculate the spine for wooden arrows. (Measured at 28” centres Recurve & Longbow Chart Bow Weight Arrow Length at Draw Length 24" 25" 26" 27" 28" 29" 30" 31" 32" (lbs.) 20-25 <30 <30 <30 <30 <30 <30 30-35 35-40 40-45 25-30 <30 <30 <30 <30 30-35 35-40 40-45 45-50 50-55 30-35 <30 <30 <30 30-35 35-40 40-45 45-50 50-55 55-60 35-40 <30 <30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 40-45 <30 30-35 35-40 40-45 45-50 50-55 55-60 60-65 65-70 45-50 30-35 35-40 40-45 45-50 50-55 55-60 60-65 65-70 70-75 50-55 35-40 40-45 45-50 50-55 55-60 60-65 65-70 70-75 75-80 55-60 40-45 45-50 50-55 55-60 60-65 65-70 70-75 75-80 80-85 60-65 45-50 50-55 55-60 60-65 65-70 70-75 75-80 80-85 85-90 65-70 50-55 55-60 60-65 65-70 70-75 75-80 80-85 85-90 90-95 Here too is a dial chart for a home made spine tester. (Remember to compensate for the strength of the spring if you decide to make one.) The chart is designed for arrows measured at 28” centres with a 2lb weight. Information about the importance of correct arrow spine. Before we go on, please note that the official term is "spine" - as in backbone. Not "spline" - as in gears and sprockets. Arrow spine refers to the arrow's degree of stiffness - how much the arrow resists being bent. Some arrows are very stiff, others are very limber. And if you ever intend to achieve serious accuracy with your compound bow, you'll need to choose an arrow that's just stiff enough - but not too stiff for your particular bow setup. Most people think an arrow flies just like it looks when at rest - perfectly straight. But nothing could be further from the truth. Once fired from a bow, an arrow immediately begins flexing and oscillating. That's not a defect. Each arrow bends and flexes in a particular cycle as it leaves the bow (archer's paradox). If the timing of the cycle is correct, the tail of the arrow clears the bow without making contact with the arrow rest, riser, or cables. If the timing of the cycle is not correct due to improper arrow spine, the over- or under-oscillation of the arrow results in serious fletching contact and/or paper-tune tears which cannot be corrected. So we have to get this one right. Determining Factors which Affect Arrow Spine There are three main ingredients which determine an arrow shaft's general spine characteristics: (1) the stiffness of the actual shaft material (2) the length of the shaft (3) the tip weight that will be used But it's not quite as simple as 1-2-3. How stiff an arrow is when it's sitting still on the workbench, and when it's busy accelerating from 0-180 mph as it's fired from the bow, are totally different issues. When the arrow is at rest, we refer to its stiffness characteristics as static spine. But when that same arrow is in motion, its stiffness is a matter of dynamic spine - which adds more ingredients into our consideration pot. So pay attention. This gets a little tricky. Static Arrow Spine If you support an arrow shaft at two points a given distance apart, and then hang a weight in the middle of the arrow - the weight will cause the arrow shaft to sag. How much the shaft resists this type of bending would be a function of the arrow's static spine. The actual static spine of the arrow shaft is determined by the elasticity of the materials in the shaft and the geometry of the shaft. In multi-layered arrows (carbon/aluminium, etc.) the bonding materials also contribute to the static spine. The inside diameter, the cross-section shape, and the thickness of the material all contribute to the static spine of the shaft material. However, arrows don't perform under static conditions - like a floor joist or a curtain-rod. Arrows perform under dynamic conditions, with motion. A hanging weight doesn't really represent how forces are applied to arrows when they're actually shot, so static spine is really used as only a benchmark for predicting dynamic spine. Dynamic Arrow Spine Unless your arrow shaft breaks or is altered, its static spine remains the same throughout its life. But your arrow's dynamic spine can change dramatically depending on how it's used. The real meat-n- potatoes of arrow performance relies on the arrow's dynamic spine. The dynamic spine is how the arrow actually bends when shot - and there are many factors which affect the dynamic spine. The static spine of the shaft is only part of the equation. As you fire the arrow, the explosive force of the bow compresses the shaft and it momentarily bends under the strain. The more powerful the bow, the more the arrow bends. So the dynamic spine of two identical arrows, shot from two different bows of varying output, could be drastically different. If your arrow has the proper amount of dynamic spine when shot from your modern 70# hard-cam bow - its stiffness is just right - not too limber - not too stiff. But, if you take that same arrow and shoot it out of your son's 40# youth bow, it will be dramatically too stiff. The arrow will have too much dynamic spine. Likewise, if you shoot your son's arrows in your 70# bow, it's likely the arrows will be dramatically too limber - not enough dynamic spine. Determining a proper dynamic spine is a bit more complex and requires examination of several contributing factors. Shaft Length Affects Dynamic Arrow Spine When an arrow is fired it bends because it is effectively being compressed. The arrow is momentarily trapped between the forward motion of the string and the static load of the arrow's tip. And the longer the shaft is, the more easily this compressive force can bend it. Imagine a brand new pencil. If you put each end of the pencil between your palms and began compressing the pencil by squeezing your palms together, this would be similar to the forces that cause an arrow to bend when shot. If you had two pencils, one standard length and one that was 2 ft. long, you would get very different results when you tried the compress them. A short pencil is surprisingly stiff and resists bending this way. But the long pencil would bend easily under the compressive load between your palms. So although the shaft material (wood & pencil lead) would be the same for each of your tests, the shorter pencil would exhibit more spine stiffness - it would act stiffer. The longer pencil would exhibit less spine stiffness - it would act more limber. This is similar to how arrow length affects dynamic arrow spine. The shorter an arrow shaft is, the more dynamic spine stiffness it will exhibit under acceleration. The longer the arrow shaft, the less dynamic spine stiffness it exhibits under acceleration. So if you change your arrow length, you must consider how that affects your arrow spine requirements. Tip Weight Affects Dynamic Arrow Spine Every arrow should have a tip. The tip is the business end of the arrow. It could be a simple steel practice point, a razor sharp hunting broadhead, a small-game judo tip, or a number of other tips designed for a variety of purposes. Each of these arrow tips is also designed to a specific grain weight. The most popular weights are 75gr, 85gr, 90gr, 100gr, and 125gr. However, some specialty tips can be much lighter or heavier. OK. Now remember how a bow compresses the arrow shaft? It's not hard to figure out what's pushing in one direction - the forward movement of the bow's string. That's an easy one. But what force pushes back the other direction? You can't get that kind of compression if you don't have two opposing forces - one pushing on each end of the shaft, right? So what pushes on the other end? Oddly enough, it's the arrow's TIP. Of course, the tip doesn't actively do anything. It's just a weight - hanging out at the end of the shaft. But surely you must remember learning about Newton's Laws of Motion. Remember the one that says "an object at rest tends to stay at rest unless acted upon by a force?" Well think of it this way. The arrow's tip is the "object at rest," and the forward movement of the string is the "force." The stationary mass on the end of the arrow resists the forward motion of the string, and since the heavy tip of the arrow is where most of the arrow's mass is concentrated, that's the area of the arrow that resists the most. So the forward motion of the string and the resistance of the tip at rest create the opposing forces. So, the greater the tip weight, the greater the compression (and flexing) of the arrow shaft when it's shot. The lighter the tip, the lesser the compression (and flexing) of the arrow shaft when it's shot. So a heavy tip DECREASES an arrow's dynamic spine (makes it act more limber). A lighter tip INCREASES an arrow's dynamic spine (makes it act more stiff). This idea is a bit more abstract, so consider a final dramatic example to illustrate the concept. Imagine if you screwed a bowling ball on the end of an arrow and tried to shoot it. Upon firing the bow, the arrow shaft would compress between the forward motion of the string and the bowling ball. The arrow would bend dramatically as the bowling ball started to grudgingly inch forward. This would be an extreme example of how a heavy tip would reduce the arrow's dynamic spine. So remember, lighter tips make an arrow act stiffer. Heavier tips make an arrow act more limber. Macho-Man Checkpoint In sections #4-5, we'll discuss the topic of tip weight selection and explore its effects on arrow mass, front-of-centre balance, loss of shot trajectory, and kinetic energy in greater detail. But for now, it's worth noting that some archers are hopelessly stricken by the Macho-Man Syndrome when it comes to choosing arrows and arrow tips. Some guys simply cannot dispense with the macho idea that bigger is better. We assure you, bigger is not necessarily better - at least not when it comes to selecting arrows and arrow components. Choosing an excessively stiff arrow shaft and/or an excessively heavy arrow tip will likely yield no benefit whatsoever to most bowhunters. In fact, MMS sufferers are often at a technical disadvantage to other bowhunters with proper setups. With today's hot new compound bows often pumping out 60, 70, even 80+ ft-lbs of kinetic energy, much of the "old school" thinking about hefty arrow mass and heavy tip weights is no longer applicable. If you absolutely must supersize some part of your bowhunting gear, get an extra big bow case. But get arrows that actually fit your bow. Bow Output Affects Dynamic Arrow Spine. The physical features of the arrow (the shaft's static spine, the shaft length, and the arrow's tip weight) all play a part in giving the arrow its spine characteristics. But as we mentioned earlier, the arrows final dynamic spine (how much it will actually flex when shot) will also depend greatly on the output of the bow. Your draw weight, draw length, cam-type, let-off percentage, and bow efficiency all contribute to the actual output of the bow. And bows with more powerful outputs will require stiffer arrows to achieve the proper dynamic spine when shot. Bows with less powerful output will require more limber shafts. Fortunately, the engineers have already crunched the numbers for us on their spine selection charts. But before we go to the charts, you should understand which attributes affect the output of a bow and the spine requirements of the arrow. Most arrow manufacturers publish charts which take some, or all, of these bow output factors into account when recommending a particular arrow spine size. Less Arrow Spine Required More Arrow Spine Required Lighter Draw Weight Heavier Draw Weight Shorter Draw Length Longer Draw Length Lighter Tip Weight Heavier Tip Weight Less Aggressive Cam More Aggressive Cam More Let-Off % Less Let-Off % Less Efficient Bow More Efficient Bow Basic Arrow Spine Application Charts Some arrow manufacturers have very complex charts that take many variables into account. But other arrow manufacturers offer a more simplified chart with an arbitrary number system, like the sample chart on the right which just references draw weight and arrow length. If you go by the simple chart method, then you'll need to apply a little common sense if your particular bow setup isn't exactly "average." For example, if you shoot a typical 310 fps compound bow, with normal 100 grain tips, and 75% let-off, all you'll need to do is follow the chart. If your bow is set for 60# and you use 29" arrows, you just follow the dots on the chart and choose the 2000 spine size. Easy! But what if you shoot a very aggressive speed-bow with an IBO speed over 340 fps ... say a PSE X- Force or a Bowtech Destroyer 350? In that case, your bow will have more output than an average 60# bow, so you would need to accommodate by choosing a little stiffer spine like the 3000 shaft. So be prepared to use your best judgment, should your bow setup have some special characteristic that needs extra consideration. If you would rather not use the simplified method, then we suggest you get to know the concept of actual spine deflection. Spine Deflection Measurements. Sometimes an arrow's spine stiffness is expressed as a more technical measurement, called a spine deflection. According to the modern standards (ASTM F2031-05) an arrow's official spine deflection is measured by hanging a 1.94 lb. weight in the centre of a 28" suspended section of the arrow shaft (not to be confused with the old AMO standard of 2 lb. and 26"). The actual distance the 1.94 lb. weight causes the shaft to sag down is the arrow's actual spine deflection. For example, if a 1.94 lb. weight causes the centre of a 28" arrow to sag down 1/2 inch (.500"). Then the arrow's spine deflection would be .500". Stiffer arrows will, of course, sag less. More limber arrows will sag more. So the stiffer the arrow is, the LOWER its spine deflection measurement will be. The more limber an arrow is, the HIGHER its spine deflection measurement will be. Spine Consistency. Remember how we mentioned the cut-throat squabble about arrow straightness? Well, the same is true for spine consistency. 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. This creates an imbalance in the spine consistency of the arrow, such that the arrow is a bit stiffer 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 amounts of spine variance are realistically inconsequential to the weekend bowhunter and backyard enthusiast. But that doesn't stop the arrow companies from bickering about who have 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
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