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Basic Tuning

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Bow tuning is adjusting the bow to the archer's style of shooting to achieve the best performance and achieve the best arrow flight.
Tuning the bow and arrow setup go hand in hand with the archer's shooting style.
To get the most from bow tuning the archer's shooting style must be consistent.

There are four main variables that effect bow performance

1 Bowstring Materials

2 Brace Height

3 Arrow Nocking Point

4 Pressure Button

5 Technical terms for beginners

Dacron B50 - (strength per strand = 22.5 kg. , stretch = 2.6%)
because of its durability, it is used mainly on beginners equipment and compound bows fitted with steel cables. It is easy to maintain and can last several years.

Kevlar 7-11 - (strength per strand = 31.8 kg. , stretch = 0.8%)
is a material with higher density, smaller diameter and lighter than Dacron which will give a faster arrow speed. (approx. 2 metres per second).
There are two problems with this material, the first is due to its limited stretch which causes increased stress in the bow limbs.
Check with the bow manufacturer if a Kevlar bowstring can be used.
The second problem is its durability. The bowstring may only last 1000 shots before breaking as it tends to fatigue due to bending at the nocking point.

Fastflite - (strength per strand = 45.5 kg. , stretch = 1.0%)
is one of the newer materials that can be used. It has the durability of Dacron and even greater arrow speed than Kevlar as it is lighter.
As the material has less stretch than Dacron, it is advisable to check with the bow manufacturer, if it can be used.
It is made from a polyethylene derivative giving it a 'plastic' look and feel. It is also very slippery, so the servings have to be wrapped very tight otherwise they will slide.
Special serving material has been developed to help overcome this problem.

Fastflite S4 - (strength per strand = 73 kg. , stretch = less than 1.0%)
is the latest material on the market. It is made from a composite of 50% Fastflite and 50% Vectran making the strands thicker.
Therefore approx. half the number of strands are required as for a Fastflite string.

1 Bowstring Materials

Brace Height is measured from the centre of the bow grip to the bowstring at 90 degrees.
Most bows will have a recommended brace height given by the manufacturer.
If the brace height is not known, then a rough guide for recurves is:-
70 inch bow = 8.50 to 9.75 inches,
68 inch bow = 8.25 to 9.50 inches,
66 inch bow = 8.00 to 9.25 inches.
64 inch bow = 7.75 to 9.00 inches.

The ideal brace height for a bow is one that produces the quietest release with the least amount of vibration in the bow.

Brace Height Tuning

Step 1.
Set the brace height at the bow manufacturer's recommended minimum.
(A slightly longer bowstring may have to be used as the bowstring must still have enough twists in it to keep it round.)

Step 2.
Shoot a few ends of arrows at close range and note how the bow performs.

Step 3.
Increase the brace height by putting 5 more twists in the bowstring.
(Make sure to twist in the same direction as this will shorten the bowstring. Also check and adjust the nocking point position.)

Step 4.
Shoot another few ends of arrows and note how the bow performs.

Step 5.
Repeat these steps until the recommended maximum brace height is reached.

Step 6.
Somewhere between the minimum and maximum heights, the bow should perform at its quietest and with least vibration.
Where it does this, is the ideal brace height for the bow with this particular type of bowstring. Keep a record of this brace height for future reference.

To help your shooting, the brace height must remain consistent. Any variation in distance will effect the arrow flight, so always check the brace height before shooting.
Bowstrings stretch over time or broken strands can lower the brace height

2 Bracing Height

 

To obtain correct arrow flight, a point on the bowstring must be found at which the force from the bowstring acts directly inline with the arrow.
A starting point is generally somewhere between 3 to 10mm (1/8th to 3/8th inches) above 90 degrees to the arrow rest.
This position is due to using two fingers below the arrow and one finger above the arrow to pull the bowstring
and seeking to find the balance point of the forces on the bowstring.

Nocking Point Tuning

Step 1

The quickest way I have found to tune a Nocking Point location is to use the 'Paper Tuning' method.
A frame is placed about 2 metres (6 feet) in front of the target.
A sheet of paper is placed taunt over the frame.
The archer then stands about 1 metre ( 3 feet) in front of the frame and shoots the arrows through the paper.
From the direction of the tear in the paper, the nocking point can be adjusted.

The paper tear on the left indicates that the nocking point is too high.
The paper tear on the right indicates that the nocking point is too low
.

Step 2

Adjust the nocking point location indicated by the direction of the paper tears above.
Shoot through a new sheet of paper and check the direction of the paper tears.
Keep repeating until the smallest paper tears are achieved.
Acceptable paper tears are shown in the picture at left, as perfect paper tears may not be possible due to other factors.

Step 3

Note the exact nocking point location for future reference.
                Always check your nocking point location before shooting.
                (If you can't get the paper tears to look like those above, it may be that your
                 arrows are 'under-spined' - too small for the draw weight of the bow.)

3 Arrow Nocking Point

Pressure buttons usually come with three different insert springs.
A soft spring, medium spring and hard spring.
For tuning, it is best to start with the medium spring and adjusting the thread to the rear of the spring to about half way in.
Adjust the 'Centre-Shot' position of the arrow on the arrow rest by winding the plunger button into or out of the riser.
To do this, nock the arrow on the bow, then looking from the rear of the arrow, align the bowstring with the centre of the top and bottom limbs,
then check the alignment of the arrow shaft to the bowstring.
For bows shot with fingers, the correct alignment should be 'Outside Centre-Shot' position.
Only the diameter of the arrow at the point should be to the left of the bowstring.
The reason for this position is to counter-act the slight sideways motion of the bowstring on release from the fingers.
The 'Full Centre-Shot' position should only be used for compound bows shot with release aids.
To align 'Full Centre-Shot' on a compound bow, align the bowstring with the top and bottom wheels, then align the arrow shaft with the bowstring.

A 'Pressure Button' can be used when the bow riser has a threaded sleeve fitted.
The arrow rest has to be adjusted so that the centre of the arrow and the centreline of the pressure button align.
The pressure button has two purposes:-
The first is to adjust the horizontal position of the arrow as it sits on the arrow rest to achieve 'centre shot'.
The second is to absorb the initial bend of the arrow as it is released by adjusting the amount of spring pressure on the plunger button.
These adjustments will achieve straighter arrow flight when the bow is 'tuned'.

3 Pressure Button

Technical Terms for Beginners

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5 Technical Terms for Beginners