Post by SPIKER on Jan 5, 2010 19:10:18 GMT -5
I read this online somewhere , and thought it was interesting. 
The evolution of the arrow shaft began when the first bow and arrow set was invented. Historians state that this happened sometime during the Paleolithic era (35,000 to 8,000 BC.) Someone came up with the idea that, instead of throwing a spear at their food of choice, they could use a large "stick" and a piece of vine or twine, to propel a smaller spear at a higher rate of speed and harvest their food more efficiently by using a greater amount of the force applied to this small spear. It is my guess that they built a bow and several arrows and practiced like crazy to become proficient. It took patience to find the right material to fashion arrows from which would yield good, consistent arrow flight For 1000's of years, man used wood to make his arrows. Some archers still use wood but, like all of man's activities, study and innovation resulted in improvements to the materials used to make arrows, as well as bows and bow accessories.
The first step up from wood was aluminum. Wood began as the material of choice because it could be shaped and straightened into arrow shafts. Through experimentation, it was found that a straight arrow shaft would fly more accurately than a shaft which was less straight. Wood was used as the sole material for arrow shafts until man discovered that metals could be mined from the earth, heated and molded into a desired shape. It was found that when the first metals, such as bronze, copper and iron, were used as arrow shafts, they were much too heavy and would fly only short distances. These metals became useful as points for arrows as they could be more easily sharpened than stones, which were originally used as arrow points. According to the United States Geological Survey, Aluminum is the second most abundant metallic element in the earth's crust, with Silicon taking top honors. Metallic aluminum was first produced by a Danish chemist, Hans Oersted, in 1825. It is about 1/3 the weight, by volume, of steel or copper and is more easily machined and cast.
The aluminum arrow story begins in 1939 when James Easton first began to experiment with aluminum as an arrow-shaft material. Two years later, Larry Hughes was the first archer to win the American National Archery Championship while using aluminum arrows. James Easton continued to develop production techniques which would yield a more consistent aluminum arrow shaft. Easton Aluminum produced the first trademarked arrows in 1946, model no. "24 SRT-X", offering them for sale to the general public. In 1955, the popular XX-75 arrow shafts were added to Easton's arrow line. Changes in aluminum arrow shafts have been few ever since as XX-75's continue to dominate the market and most archers start off using the XX-75 shafts. Aluminum shafts provided greater consistency of weight, balance and arrow flight, when compared to the wooden shafts used by archers previously.
In 1969, Holless Wilbur Allen was granted a U.S. Patent on his invention of the compound bow, which revolutionized archery in the United States. This invention also helped to give greater value to the aluminum arrow shaft. Aluminum shafts, vs. wooden shafts, have a greater tolerance to the forces applied to them when shot from a compound bow. When a compound bow is drawn, the amount of effort used by the archer increases as the bowstring is drawn back and then drops off during approximately the final 3rd of the total draw length, known as let-off. When the bowstring is released and the energy stored in the limbs is applied to the arrow: the bowstring travels forward and the maximum amount of energy is applied quckly to the arrow at the strings let-off point. In contrast, non-compound bows apply a steady amount of energy to the arrow when the bowstring is released and travels forward. Wooden shafts, due to their natural inconsistency in stiffness, would possibly explode into splinters if fired from a compound bow. James Easton, and other metallurgists, had the technical knowledge required to measure the stiffness or "spine" of an arrow shaft which would be consistent throughout the shaft due to the manufacturing process. The compound bow also possesses the ability to be adjustable in draw weight. This would require a greater selection of arrow spines as draw weight changes would change the forces applied to the arrow shaft. Changes in thickness of shaft walls and the diameter of the shafts would effect the spine of the arrow shaft, as would arrow shaft length and the weight of the arrow head used by the archer. Easton uses a 4 digit number to identify their aluminum shafts. This number is actually 2 2-digit numbers; the first number indicates the outside diameter of the arrow shaft in sixty-fourths of an inch and the second number indicates the wall thickness of the shaft in thousandths of an inch. A "2215" shaft would be 22/64" in diameter and have a wall thickness of 0.015".
Release aids have become popular with archers over the last 20 years due to greater consistency in arrow flight, when compared to arrows shot by drawing and releasing the bowstring with fingers. Slow motion film techniques have helped us study these issues to understand the reasons why. When the bowstring is released by the archer's fingers, the string will move around the fingers horizontally in one direction and then correct itself by moving in the other direction as it travels forward. The arrow shaft will also flex as the bowstring travels forward. This flexing of the arrow shaft is know as "archer's paradox". If the stiffness (spine) of the arrow shaft is too low, the forces applied to the shaft when the bowstring is released could cause the arrow shaft to break. The correct arrow spine will allow for the shaft to handle the paradox and stop flexing a short distance after it has left the bow which will yield good arrow flight as the feathers of the arrow control it's flight. Release aids minimize the amount of string movement from side to side and add consistency because the string movement is the same with each shot. Arrows used with releases require a shaft with a stiffer spine than finger-shot arrows because there is less flexing required to provide good arrow flight.
Now that we have an idea of arrow flight characteristics let's look at the advantages of shaft materials. Wood was the first material to be used for arrow shafts. It was easy to obtain but required proper manufacture and a lot of testing to come up with a wooden shaft which flew well consistently. It became obsolete as a shaft material with the advent of the compound bow, although it is still used today by traditional (non-compound) archers. A good number of the non-compound archers have adopted aluminum as their arrow shaft material of choice, due to it's availability and durability in comparison to wood. Easton aluminum has provided all archers with the "Easton Arrow Shaft Selection chart", which shows which of their shaft sizes should be used, based on details such as the type of bow, type of compound bow cam, arrowhead weight and draw weight and draw length. This has made it easy for the average archer to determine which aluminum shaft(s) will work well with their bow, simply by using the Easton chart. Aluminum arrows are commonplace and hold a good portion of the arrow shaft market. This makes them relatively inexpensive and easily replaced when needed, simply by going to the local bow shop or ordering them through a mail order catalog.
Carbon arrows were first developed, again by Easton Archery, in 1983. When carbon arrow shafts were first introduced and hunters became aware of their existence, rumors began to fly that the shafts were brittle and , when broken, they would splinter into long, sharp, pine-needle-like fragments. Sure, there were early problems but this occurs in the early stages of any new innovation. It takes a while to get it tweaked. Carbon arrow shaft production evolved to produce spiral fiber-wrapping and cross weaving of the carbon which increased the durability and strength of the carbon. Carbon arrows have the ability to maintain their straightness. It has been said that "they're either straight or their broken". In contrast, I personally have a collection of aluminum shafts, in a box in a back room, that have are no longer useable because they have been bent or dinged by other arrows when shooting. Aluminum arrows can be straightened but I think that once you bend an arrow, you weaken the shaft at the inside-bend. I have switched exclusively to carbon arrows and don't see any reason to go back, in my opinion. Not to say that carbon is better than aluminum if that's what you shoot and it works well for you. It's a confidence-in-your-equipment issue.
The evolution of the arrow shaft began when the first bow and arrow set was invented. Historians state that this happened sometime during the Paleolithic era (35,000 to 8,000 BC.) Someone came up with the idea that, instead of throwing a spear at their food of choice, they could use a large "stick" and a piece of vine or twine, to propel a smaller spear at a higher rate of speed and harvest their food more efficiently by using a greater amount of the force applied to this small spear. It is my guess that they built a bow and several arrows and practiced like crazy to become proficient. It took patience to find the right material to fashion arrows from which would yield good, consistent arrow flight For 1000's of years, man used wood to make his arrows. Some archers still use wood but, like all of man's activities, study and innovation resulted in improvements to the materials used to make arrows, as well as bows and bow accessories.
The first step up from wood was aluminum. Wood began as the material of choice because it could be shaped and straightened into arrow shafts. Through experimentation, it was found that a straight arrow shaft would fly more accurately than a shaft which was less straight. Wood was used as the sole material for arrow shafts until man discovered that metals could be mined from the earth, heated and molded into a desired shape. It was found that when the first metals, such as bronze, copper and iron, were used as arrow shafts, they were much too heavy and would fly only short distances. These metals became useful as points for arrows as they could be more easily sharpened than stones, which were originally used as arrow points. According to the United States Geological Survey, Aluminum is the second most abundant metallic element in the earth's crust, with Silicon taking top honors. Metallic aluminum was first produced by a Danish chemist, Hans Oersted, in 1825. It is about 1/3 the weight, by volume, of steel or copper and is more easily machined and cast.
The aluminum arrow story begins in 1939 when James Easton first began to experiment with aluminum as an arrow-shaft material. Two years later, Larry Hughes was the first archer to win the American National Archery Championship while using aluminum arrows. James Easton continued to develop production techniques which would yield a more consistent aluminum arrow shaft. Easton Aluminum produced the first trademarked arrows in 1946, model no. "24 SRT-X", offering them for sale to the general public. In 1955, the popular XX-75 arrow shafts were added to Easton's arrow line. Changes in aluminum arrow shafts have been few ever since as XX-75's continue to dominate the market and most archers start off using the XX-75 shafts. Aluminum shafts provided greater consistency of weight, balance and arrow flight, when compared to the wooden shafts used by archers previously.
In 1969, Holless Wilbur Allen was granted a U.S. Patent on his invention of the compound bow, which revolutionized archery in the United States. This invention also helped to give greater value to the aluminum arrow shaft. Aluminum shafts, vs. wooden shafts, have a greater tolerance to the forces applied to them when shot from a compound bow. When a compound bow is drawn, the amount of effort used by the archer increases as the bowstring is drawn back and then drops off during approximately the final 3rd of the total draw length, known as let-off. When the bowstring is released and the energy stored in the limbs is applied to the arrow: the bowstring travels forward and the maximum amount of energy is applied quckly to the arrow at the strings let-off point. In contrast, non-compound bows apply a steady amount of energy to the arrow when the bowstring is released and travels forward. Wooden shafts, due to their natural inconsistency in stiffness, would possibly explode into splinters if fired from a compound bow. James Easton, and other metallurgists, had the technical knowledge required to measure the stiffness or "spine" of an arrow shaft which would be consistent throughout the shaft due to the manufacturing process. The compound bow also possesses the ability to be adjustable in draw weight. This would require a greater selection of arrow spines as draw weight changes would change the forces applied to the arrow shaft. Changes in thickness of shaft walls and the diameter of the shafts would effect the spine of the arrow shaft, as would arrow shaft length and the weight of the arrow head used by the archer. Easton uses a 4 digit number to identify their aluminum shafts. This number is actually 2 2-digit numbers; the first number indicates the outside diameter of the arrow shaft in sixty-fourths of an inch and the second number indicates the wall thickness of the shaft in thousandths of an inch. A "2215" shaft would be 22/64" in diameter and have a wall thickness of 0.015".
Release aids have become popular with archers over the last 20 years due to greater consistency in arrow flight, when compared to arrows shot by drawing and releasing the bowstring with fingers. Slow motion film techniques have helped us study these issues to understand the reasons why. When the bowstring is released by the archer's fingers, the string will move around the fingers horizontally in one direction and then correct itself by moving in the other direction as it travels forward. The arrow shaft will also flex as the bowstring travels forward. This flexing of the arrow shaft is know as "archer's paradox". If the stiffness (spine) of the arrow shaft is too low, the forces applied to the shaft when the bowstring is released could cause the arrow shaft to break. The correct arrow spine will allow for the shaft to handle the paradox and stop flexing a short distance after it has left the bow which will yield good arrow flight as the feathers of the arrow control it's flight. Release aids minimize the amount of string movement from side to side and add consistency because the string movement is the same with each shot. Arrows used with releases require a shaft with a stiffer spine than finger-shot arrows because there is less flexing required to provide good arrow flight.
Now that we have an idea of arrow flight characteristics let's look at the advantages of shaft materials. Wood was the first material to be used for arrow shafts. It was easy to obtain but required proper manufacture and a lot of testing to come up with a wooden shaft which flew well consistently. It became obsolete as a shaft material with the advent of the compound bow, although it is still used today by traditional (non-compound) archers. A good number of the non-compound archers have adopted aluminum as their arrow shaft material of choice, due to it's availability and durability in comparison to wood. Easton aluminum has provided all archers with the "Easton Arrow Shaft Selection chart", which shows which of their shaft sizes should be used, based on details such as the type of bow, type of compound bow cam, arrowhead weight and draw weight and draw length. This has made it easy for the average archer to determine which aluminum shaft(s) will work well with their bow, simply by using the Easton chart. Aluminum arrows are commonplace and hold a good portion of the arrow shaft market. This makes them relatively inexpensive and easily replaced when needed, simply by going to the local bow shop or ordering them through a mail order catalog.
Carbon arrows were first developed, again by Easton Archery, in 1983. When carbon arrow shafts were first introduced and hunters became aware of their existence, rumors began to fly that the shafts were brittle and , when broken, they would splinter into long, sharp, pine-needle-like fragments. Sure, there were early problems but this occurs in the early stages of any new innovation. It takes a while to get it tweaked. Carbon arrow shaft production evolved to produce spiral fiber-wrapping and cross weaving of the carbon which increased the durability and strength of the carbon. Carbon arrows have the ability to maintain their straightness. It has been said that "they're either straight or their broken". In contrast, I personally have a collection of aluminum shafts, in a box in a back room, that have are no longer useable because they have been bent or dinged by other arrows when shooting. Aluminum arrows can be straightened but I think that once you bend an arrow, you weaken the shaft at the inside-bend. I have switched exclusively to carbon arrows and don't see any reason to go back, in my opinion. Not to say that carbon is better than aluminum if that's what you shoot and it works well for you. It's a confidence-in-your-equipment issue.
