Parts of a Compound Bow: What You Must Know Before Buying One
If you’ve already decided to get into the sport of archery, bow hunting, or bow fishing, the most important thing you have to do is to choose the right kind of compound bow to use. The archery market is flooded with many good quality brand names to choose from, as well a variety of models specifically made in relation to the type of archery you are getting into. If you have no experience whatsoever in such things, you can always do some extensive research on related topics before deciding the brand and type you are going to purchase.
Parts of a Compound Bow: The Basic mechanism of a compound bow
Let’s take a look at the basic mechanism of a compound bow, before delving into the individual parts and their features.
The first compound bow came into being in the year 1966 invented by a Missouri Bow hunter Holles Wilbur Allen; it was given a United States patent in the year 1969. A modern compound bow is a bow makes use of a leveling system to bend or pull the limbs with cables and pulleys. Compared to the recurve bow or longbow its limbs are made much stiffer than usual. It is this stiffness that makes it able to shoot arrows with more power and faster due to the greater power stored in the limbs.
The strings are attached to a cam or pulley, with one or both has one or more cables attached to the opposite limb. This system enables virtually any archer to pull back the strings effortlessly and efficiently. The wheels turn every time the string is drawn back, which causes the pulleys to pull the cables, and causes the limbs to bend.
Once the limbs are drawn back by the archer, energy is stored in the limbs, ready to shoot at arrow towards its intended target. A compound bow’s accuracy is further enhanced by the use of sight pins, anti-vibration systems, draw-stops, and many more elements not found in recurve and long bows.
When combined, the many different compound bow parts and accessories make a superb piece of shooting equipment.
Parts of a Compound Bow: Individual components and their features
A compound bow might be in principle a simple piece of archery equipment, but using one, and getting familiar with all the parts of a compound bow and their function is an entirely different story.
Take a look at the compound bow parts diagram below to become familiar with the nomenclature and position of each element within a compound bow.
Click on the compound parts names listed below to explore their characteristics and specific function.
The central riser
This is the central mount for other parts such as the sights, stabilizers, quivers and limbs. Risers are mainly made out of aircraft-grade aluminium alloy and designed to be as rigid as possible. Some compound bows feature carbon risers, which are lighter, stay warm and are stiffer.
Each type of riser will feature many subtle differences, but there are currently three main styles to choose from: straight, deflex, and reflex.
Reflex style risers can be spotted easily. This style curves away from the natural curvature of the limbs. This type produces a faster speed as it works to reduce a bow’s brace height. Most new compound bows will feature a reflex style riser.
The exact opposite of the reflex riser is the deflex riser. This style will follow the curvature of the limbs instead of curving away from it. This will work to increase brace height and can also create slower arrow speed. This style of a riser is more forgiving to shoot and definitely more accurate. They’re also the least common type of riser to use on modern compound bows that are used primarily for hunting.
The straight riser will fall somewhere in between the reflex and deflex styles. Straight risers are technically reflex risers, but they feature a less extreme curvature. They’re also reasonably forgiving and fast. However, like the deflex riser, straight riser models are not so common in the bow world.
The materials used for a riser, as well as the size and weight, will affect the bow’s cost. However, it doesn’t really affect the longevity, accuracy, and performance of the bow. There are a couple of common ways that risers are constructed: machined and cast. Some risers are also made from a lightweight carbon fiber, however, these are not very common.
The cast riser is just as reliable, accurate and strong as machined risers, and are usually available for a fraction of the cost. But their weight and size can be a big disadvantage. Cast risers often feature a thicker grip section and are heavier than machined risers.
Off all the riser styles, machined risers are the lightest. These risers feature a smaller grip that will usually fit most hands better compared to a cast riser. However, this style is also pretty expensive to produce.
The bow limbs
The limbs are the flexible fiberblass planks made of composite materials or composites, which are made out of two or more constituent materials with different chemical or physical properties engineered to be capable of taking high compressive and tensile forces. The draw weight of a compound bow is adjusted by turning the limb bolts, which are usually locked into the riser with locking bolts located just below the top limb or above the bottom limb. Check out our guide on how to adjust a compound bow to find out how to increase or decrease the draw weight setting on your bow.
Much like the riser, limbs also come in different styles and shapes. Solid limbs are made from just one fiberglass part, which constitute both limbs and riser in one piece. Split-limbs are made up of two thin limbs connected to the riser. Split-limbs are claimed to be more durable and vibrate less than solid limbs (which in turn helps taming the noise).
Most modern compound bows, particularly hunting ones, feature parallel limbs, as opposed to more traditional bows that have a “D” shape. Parallel limbs are usually more silent and have less recoil when firing the arrow.
The bowstring and the cables
The bowstring is responsibile for launching the arrow, while the cables run from cam to cam, moving the cams as the bowstring is drawn.
The bow string and the cables are mainly made of high-modulus polyethylene. This is a high impact-strength material, highly resistant to corrosive abrasion and chemicals, self-lubricating, has extremely low moisture absorption and has significantly lower coefficient friction as compared to nylon. It is comparable to Teflon and is tasteless, non-toxic and odorless. This highly modern material is meant to have superior tensile strength and minimal stretch ability. This is what makes the compound bow able to transfer all the stored energy of its limbs as durably and efficiently as possible to the arrow. Models of compound bows made earlier had plastic-coated steel cables.
The cable guard and the cable slide
The cable guard is a fiberglass rod that holds the cables aside to clear arrow fletching and to prevent the cable from interfering with the arrow line of fire. Attached to the cable guard is the cable slide, a small plastic piece that is attached to the cable guard and then mounts to the cables. The cable slide, along with the guard, helps keep the cables away from the arrow and prevents cable coating wear by isolating the cables from the cable guard.
The eccentric system
The mechanical parts making up these units create the main difference in style and functionality. There are cables used to connect cams that create draw strength; this compounding action can produce great amounts of thrust and apply it smoothly to the projectile. Some cams are round, and others are elliptical in shape some have single cams at each end, and some designs incorporate double cams.
A common configuration of the compound bow presents a wheel or cam at each end of the limb, which may vary from different bow types. There are different design concepts with different ways by which the cams store power in the limbs. Four different mechanical styles are available today: single cam unit, twin cam unit, hybrid cam model, and a relatively new style called the binary cam. This last unit has had very good reviews and already boasts a strong following. These design concepts fall under a category called bow eccentrics.
The single cam system is the best compound bow for beginners, as this type of bow is the most basic of its class having the advantage of not needing to be synchronized as that of a twin cam bow. The idler wheel at the top of the limb does not provide any mechanical advantage but serves only to unroll the string when the bow is drawn. The bottom cam controls the cable as the string is drawn, and at the same time letting out the other end of the string at a controlled rate to keep the nock move straight back and forward. The changes in power cable length do not affect this type of system; when the power cable is stretched, the bow stays in tune with a single cam.
The twin cam system bows are more difficult to use due to their high sensitivity to synchronization problems. The cams will not turn over properly if either one of its harnesses is not of equal length. Twin cam bows need daily checkups and timing-tuning in order to being kept in top performing condition.
The hybrid cam (or 1.5 hybrid) are a combination of single and dual cam style. They feature two asymmetrically elliptical cam, a control one on the top, and a power one on the bottom. Their speed is often compared to that of dual cams. This type of compound bow will function the same as a solo, as the idler wheel will be replaced with another cam. But adding the second cam works to offset the movement of the nock when compared to a solo model.
Binary cams on the Infinite Edge Pro
The binary cam overcomes the problems of the twin cam by implementing a special rotation correction system that synchronizes the two cams with each shot cycle. This type of cam is also less time-consuming to maintain and requires little or no timing-tuning.
What’s the best compound bow for me?
When you have become a little bit more familiar with how a compound bow works, and what each of the individual components do, it is time to choose the right bow. We’ve put together an useful guide that will walk you through the features of the best compound bows for beginners and pro archers on the market.
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