Bow Tuning Made Easy

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Accurate shooting begins with a properly tuned bow

Today’s compound bows are intricate, high-tech pieces of equipment. Depending on whether a bow is a dual cam, a cam-and-a-half or a single-cam bow, each will be tuned just a little bit differently. That said, in general, all compound bows have interdependent parts and, as such, they must be tuned so that those components work in synch.

At the same time, it’s important to acknowledge that anything that needs tuning can, and will, eventually go out of tune. Strings stretch and parts loosen or shift, resulting in inconsistent arrow flight, general inaccuracy, slower speeds and even unnecessary noise. Assuming the bowstring and all other components are in good shape and functioning properly, any time you get inconsistent arrow flight, it’s time to see a competent technician or, if you are able, address the following key areas yourself.

 

Timing

I consider a friend of mine to be one of the finest archery technicians around. He has tuned thousands of bows over the years. He once told me that, “a majority of those who are shooting dual cam bows have timing issues.” Considering this a bold declaration, I did some research. Indeed, what I learned is that most of my friends and acquaintances were shooting bows that were improperly tuned and, in fact, often had significant timing issues.

So what is timing? Simply put, timing has to do with tiller height, or the distance from the string to the riser, for both the upper and lower limbs. In order for the cams to be in synch, they must roll over at the same time and to the same extent. If one rolls over more or less than the other, the timing will be out and you will see mostly vertical inaccuracy issues; in turn, making it impossible to achieve consistent arrow flight. Therein lies one advantage to shooting single cam bows. While timing is not an issue when dealing with a cam at one end and a wheel at the other, however, single cam bows are generally slower.

Likewise, most cams today have both a draw stop and/or markings on them for their various settings. At full draw, the cable should line up consistently between, or on, those markings on both the top and bottom cams. If it does not, then draw stop timing is out and it will probably need to be adjusted. If one or the other is out, that suggests that one of the cables has probably stretched. Twisting to shorten that cable, to bring it in line with the other, can usually rectify this. Normally you want exactly the same amount of twist in each side of the yoke. With cam-and-a-half bows, you may need to twist either the bus cable or the control cable.

 

Cam alignment

With timing taken care of, it’s best to look down the string from one cam to the other. This will allow you to confirm that both are in line with the string. If one is not, the cam will be leaning one direction and this should be rectified. Most dual-cam bows have a yoke system. With the aid of a bow press, to resolve cam lean, you can tighten (or twist) the side of the yoke that is needed to bring it back into alignment.

 

Setting the arrow rest and nock point

In order for arrows to fly true, the rest and nock point must be set in the right vertical position. One of the best ways to properly set a nock point (or D-loop) is to use a bow square. As a general rule, a nock point should be set one-eighth-of-an-inch above the zero mark. The goal is to establish a level or, most ideally, a nocked arrow that is very slightly tilted downward.

Arrow rest adjustments can also be made by attaching a level to the string serving to confirm vertical and an arrow level to confirm horizontal level or, as mentioned, a very slight downward angle to the arrow. This would mean that the bubble on the level would be just touching the back line. To test whether the rest and nock point are set properly, shoot at close range, such as 10 yards, at a target with a perfectly horizontal line. Then shoot at that same line at 20 yards. If the arrow is hitting the line at 10 yards, but below the line at 20, the nock point must be lowered slightly until it hits precisely on the horizontal line at both distances. This should set your nocking point at the right position.

 

Centre shot

Centre shot refers to alignment of your arrow rest, or the arrow itself, with the centre of the limbs. Testing centre shot involves adjusting the rest to the left or right to achieve true alignment with the string and limbs. If the arrow rest is set too far to the left or right, arrow flight will be affected, resulting in inconsistency. To the trained eye, you can eyeball centre shot can by looking through the string and down the nocked arrow. On the other hand, a trick that is widely used is to tape a piece of string to the exact centre of the top and bottom limbs. This provides a dead centre reference point. Then take an older arrow, nock it and mark it just behind the piece of vertical string. Cut the arrow at the mark and then nock the cut arrow. If centre shot is true, the piece of string should run directly down the middle of the cut arrow shaft. If not, simply adjust your rest to the right or left to achieve perfect centre shot. At this point, take the opportunity to align your sight pins with the vertical piece of string as well.

All else being equal, if centre shot is tuned and sight pins are in alignment, then pinpoint left and right downrange accuracy should be achieved at close and long distances – 10, 20, 30 yards and so on. If not, then inaccuracies will be exaggerated with greater distances. If arrows are hitting to the right, then the rest should be adjusted to the left, and vice versa, to achieve perfect alignment.

 

Paper tuning

Finally, shooting an arrow through paper provides a good indication of how your bow is tuned. Using a sheet of paper mounted taut to a stand approximately six feet away, draw and shoot an arrow. It is imperative that you shoot straight into the paper, not at an angle. It can be helpful to use a bow sight with a vertical level on it to ensure that the bow is straight up and down when you release the string. The purpose of shooting through paper is to determine if the arrow is flying straight by looking at the tear pattern in the paper. If properly tuned, there should be a small hole made by the shaft and a near perfect tear made by the fletching. If it is out of tune, there will be uneven tears and possibly a larger tear made in one direction by the shaft itself. With most bows, adjustments should be made to the rest itself. For example, if the arrow point is hitting high and left, then you will adjust the rest down and to the right until the arrow passes through the paper in perfect alignment. Again, what you want is one perfect hole in the middle, with three even tears from the fletching. When this is achieved, fine paper tuning is complete.

Watch this video to see how paper tuning is done.

 

Final adjustments

After tuning your bow, you will have to double check to make sure all screws are snug and you will need to sight in your bow again to ensure absolute accuracy.

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