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The Paper Tuning Arrow Test is the most commonly used bow tuning test for archers using compound bows with release aids. This test also works well for finger.
Typology: Exercises
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Successful tuning can only be achieved by using a properly spined arrow shaft. Initially, it is best to start with a shaft recommended by one of Easton's Arrow Shaft Selection Charts or by one of Easton's computer selection programs, the Arrow Flight Simulator or Shaft Selector “Plus.” Final verification is achieved during the tuning process. Any problems due to an improperly spined shaft will become evident during tuning. Before tuning be sure that shafts are straight, are properly fletched, and have perfectly aligned nocks (see pages 15 thru 30).
Fig. 1- Nocking Point Position
90 °
Tuning procedures for the three most popular shooting setups are described and abbreviated throughout the manual as follows: u recurve bows, using finger release (RF) u compound bows, using finger release (CF) u compound bows, using a release aid (CR) You will notice that some of the techniques of bow tuning apply to all types of bow setups and others apply to just one or two types. When separate tuning procedures are required for specific setups, find your setup within the topic and follow those specialized instructions.
Before you start any bow tuning procedures, be sure to install all accessories on your bow, i.e., the correct bowstring, bow sight, stabilizers, arrow rest, cushion plunger, etc. In other words, install all the items you intend to use when shooting. Any adjustments made to the bow or changes in bow components can affect the tune of your equipment. When tuning, it is very important to change only one variable at a time!
The first phase in achieving well tuned equipment is good preliminary equipment setup. If the initial setup is done correctly, bow tuning can be an easy process. By following the bow setup guidelines in the initial prepara- tion of your equipment, you can eliminate most or all of the possible disturbances which cause tuning problems, including false tuning indicators. A false tuning indicator would be having a high nocking point indication when the problem is actually poor clearance.
Install a moveable nocking point on the bowstring. Clamp-on types are ideal. Initially, position the nocking point on the bowstring about 1/2" (1.3 cm) above square for RF and CF and approximately 1/4" above square (0.63 cm) for CR. See Fig. 1.
1/2" RF, CF 1/4" CR
This section includes step-by-step tuning procedures for obtaining optimum performance and accuracy from your bow and arrow setup. Also included are equip- ment setup tips, and suggested solutions to most bow tuning problems.
Preliminary Bow Setup .............................................. 1 Standard Tuning Methods Bare Shaft Planing Test ...................................... 4 Paper Tuning Arrow Test ................................... 6 Short Distance Fine Tuning Test ....................... 8 Trouble-Shooting Arrow Groups ...................... 8 Bow & Arrow Adjustments .............................. 10 Broadhead Tuning ............................................ 11 Fine Tuning ............................................................... 12 Micro Tuning ............................................................ 14
This section provides instructions for properly cutting shafts and installing components. Arrow maintenance procedures are also included.
Measuring and Cutting Shafts ................................. 15 Aluminum Shaft Component Installation ............. 18 Aluminum/Carbon Component Installation ........ 20 Carbon ICS Component Installation ..................... 23 External Component Installation ........................... 24 Installing Nock Systems ........................................... 26 Additional Information ............................................ 30
A RROW TUNING AND
M AINTENANCE G UIDE
Arrow Nodes - As the arrow oscillates, the nodes remain in direct alignment to the target. This diagram clearly illustrates the front and rear node positions of the arrow. The front node is usually closer to the front end of the arrow than the rear node is to the nock end. This is due to the mass weight of the point—nodes will always be located closer to the heavier mass.
Rear Node Front Node
Finger Release (RF, CF)
When there is no pressure on the cushion plunger, the finger-released arrow is aligned slightly outside the center of the bowstring.
As the cushion plunger compresses, the nodes of the arrow come in direct alignment to the target.
Line to target Line to target
Misaligned Arrow RF, CF, CR (Incorrect Arrow Rest Position)
Compound Mechanical Release (CR)
Bow limb
Bow limb
Tape
Tape
Wheel
Wheel
Direct Line to Target
In order to have a reference point from which to adjust the arrow's left/right position on the bow, it is necessary to find and mark the exact center of the limbs on a recurve bow, or what is termed the “balanced limb center” on a compound bow.
To find the limb center for recurve bows, place a piece of masking tape across the inside of each limb a few inches from the riser. With an ink pen, make a small vertical mark on the tape in the exact center of each limb.
To find the balanced limb center location for the preliminary setup of your compound bow, place a piece of masking tape across the inside of each limb a few inches from the riser. Accurately mea- sure the width of the limb (at the tape) and place a very small pen (or pencil) mark on the tape in the exact center of each limb. Next, measure 3 / 16 " (4.8 mm) to the left of the mark (for right-handed archers) and make a larger vertical mark on the tape. (Left-handed archers place a larger mark 3 / 16 " (4.8 mm) to the right of the limb center mark.) This second mark will be used for arrow center- ing. (See Fig. 2.) This procedure is done to compensate for the amount the eccentric wheel or cam is offset from the actual center of the limb. The 3 / 16 " (4.8 mm) measure- ment is an average “offset” difference for most com- pound bows and does not need to be a precise measure- ment in the preliminary setup stage, as you will locate the true balanced limb center when performing the fine tuning procedures.
The arrow tip is aligned down the center of the bowstring. Nodes of the arrow are in alignment to the target. (Since the arrow bends vertically when using a release, the nodes stay in alignment down the center of the bowstring.)
The arrow is not positioned to leave the center of the bow—it is out too far. Nodes are not in alignment to the target.
Line to target
Front node position
Bowstring to target alignment Rear node position
The objective of arrow centering is to have the arrow leave the “theoretical” or “balanced” limb center of the bow. In actuality, it's the two nodes of the arrow shaft that should leave the center of the bow in direct alignment to the target. Releasing the string with fingers creates a horizontal bending motion within the arrow. Releasing the string with a release aid causes a slight up/down bending motion instead. Because of this, the arrows must be positioned differently for each style of release. (See Node Alignment diagram to the right). A description of these position adjustments follows.
Balanced limb center (left mark) Measured 3/16" from actual center
Actual limb center (right mark)
Compound Bow Balanced Limb Center Location
Top View of Arrow
specifications including length, type of material, type and color of serving, etc. The brace height determines the specific point at which the arrow separates from the bowstring and the amount of bend the arrow has when the separation occurs. The best brace height for your recurve or compound bow is one that allows the most compatible launch position for the arrow at the end of the bow’s “power stroke.” Locating the best brace height for your bow can significantly improve arrow grouping and shooting consistency.
Brace height is set by the compound bow manufac- turer. Sometimes changing the brace height to a slightly higher or lower position will improve arrow flight and grouping. This can be accom- plished by changing the length of the string, as described previously for recurve bows. Remember, how- ever, that changing the brace height of a compound bow affects the draw weight and draw length of the bow.
The nock tension (“snap fit”) necessary to separate the nock from the bowstring serving can be very critical, especially on light draw-weight bows (30 lbs. and under). Nock tension should be tight enough so the arrow can easily support its own weight when the arrow is hanging vertically on the bowstring (nock against the nocking point). To check this, hang your arrow vertically from the bowstring, and give the string a sharp tap with your finger on the serving about 1-2" (2.5-5 cm) from the arrow nock. The arrow should separate from the string. If it does not, the nock is probably too tight for most target archery. For hunting, a slightly tighter nock-to-bowstring fit is often preferred.
Now that you have completed the preliminary adjustments you can start the tuning process. Four methods of bow tuning are described (pp. 4 thru 14) —the Bare Shaft Planing Test, the Paper Tuning Arrow Test, Short Distance Tuning, and Broadhead Tuning.
In addition to tuning, the bare shaft test is also useful for determining if the correct shaft has been selected. If the left/right adjustments out- lined under “Fishtailing” do not cause the unfletched shafts to group with or very near the fletched shafts, then a weaker or stiffer spined shaft (based on where the arrows have impacted) must be selected. Arrows that do not fly well and do not group tightly are usually affected by one or more of the following prob- lems:
BEGINNING BRACE HEIGHT
6 4 " 8 1 / 4 " - 8 1 / 2 " (21.0 cm - 21.6 cm) 6 6 " 8 3 / 8 " - 8 5 / 8 " (21.3 cm - 21.9 cm) 6 8 " 8 1 / 2 " - 8 3 / 4 " (21.6 cm - 22.2 cm) 7 0 " 8 5 / 8 " - 8 7 / 8 " (21.7 cm - 22.5 cm)
When using carbon arrow shafts which have exter- nally fitted nocks, it may be necessary to adjust your nocking point up slightly to allow the nock to clear the arrow rest. The nock diameter is significantly larger than the shaft diameter on these arrows. A slightly higher nocking point lifts the arrow off of the arrow rest and keeps the nock from coming in contact with it, eliminating a potential clearance problem.
For clicker shooters, be sure that the arrow is well supported on the rest and not held in place by the tension of the clicker only. It is important to draw the bow a few times without the clicker to make sure the arrow can be drawn and let down without the arrow falling off the arrow rest.
Initially, set the sight pin on your bow sight over the centerline of the arrow shaft.
Not every type of bow setup uses a cushion plunger. Some archers use rests without a cushion plunger. For example, many tournament archers use a Springy™ rest, and some traditional archers use other styles of arrow rests that do not have side pressure tension adjustments. If your setup incorporates a cushion plunger, start with the spring tension set at medium.
Start with the brace height at the lower end of the manufacturer’s recommendation or use the follow- ing chart. To locate the optimum brace height for your particular bow, “twist up” the bowstring to make it shorter. This raises the brace height.
BOW LENGTH
All bows are different, even ones of the same make and model. Therefore, it is important to locate a brace height that fits your particular bow and shooting style. Shoot a few arrows at the suggested beginning brace height, then unstring the bow, add 3-4 twists to the bowstring and shoot again. Continue this process until the bow feels smoothest and quietest when shooting.
If the bowstring is too short to allow a brace height at the lower setting, you may wish to use a slightly longer string. If the string is too long to allow a higher brace height (and starts to knot-up from too many twists), you may wish to try a slightly shorter bowstring. There are many custom bowstring makers who produce strings to your exact
It is important to correct for Porpoising first. If the arrow leaves the bowstring with the nock too high or too low, a motion known as Porpoising occurs. Porpoising is caused by an incorrect nocking point location. Use the Bare Shaft Planing Test to find the correct nocking point location. Shoot at least three fletched shafts at a distance of 15 to 20 yards (or meters). Then shoot two identically- aimed unfletched shafts. Once you get the bare shafts to impact close to the fletched arrows at 20 yards (or meters), you may want to try shooting 25-30 yards (or meters) for a finer tuning indication.
If the unfletched shafts impact above the identically- aimed fletched shafts, move the nocking point up on the bowstring until both fletched and unfletched shafts strike at the same elevation. See Fig. 10.
If the unfletched shafts impact below the identically- aimed fletched shafts, move the nocking point down on the bowstring until the unfletched shafts hit at the same elevation or slightly lower than the fletched shafts.*
To assure you have eliminated Porpoising, repeat the test, shooting first the fletched, then the unfletched shafts, and make adjustments to the nocking point until both fletched and unfletched shafts impact at the same elevation.
If the arrow leaves the bow with the nock end leaning to one side or the other, Fishtailing occurs. The nock end of the arrow will appear to move from side to side as the arrow follows its flight path. See Fig. 11.
Use the Bare Shaft Planing Test to correct Fishtailing. Shoot three fletched shafts at a distance of 15 to 20 yards (meters), then shoot two identically-aimed, unfletched shafts. If the unfletched shafts impact left (stiff) of the identically- aimed, fletched shafts, as seen in Fig. 11 (for a right- handed archer), either decrease the spring tension on the cushion plunger, increase bow weight slightly (if your bow weight is adjustable), or increase arrow point weight.
If the unfletched shafts impact right (weak) of the identically-aimed, fletched shafts, as seen in Fig. 11 (for a right-handed archer), increase the spring tension on the cushion plunger, decrease bow weight slightly (if your bow weight is adjustable), or decrease arrow point weight.
Your equipment is basically tuned when the bare shafts and fletched shafts impact at the same or very near the same location. Once you have completed the finer tuning methods listed for Fine Tuning and Micro Tuning on pages 12-14, do not be surprised if the bare shaft impact changes. It is common on a well-tuned bow to have the bare shaft impact a little low and slightly stiff (to the left of the fletched shafts for a right-handed archer). Occasionally, a good tune may be achieved with the bare shaft impacting slightly weak (to the right of the fletched shafts for right-handed archers), but this is less common.
When correcting Fishtailing using the Bare Shaft Planing Test, you may have a problem adjusting the unfletched shaft's impact to that of the fletched shaft. Your arrows might be too weak (the unfletched shaft impacts to the right of the fletched shaft for right-handed archers) or too stiff (the unfletched shaft impacts to the left of the fletched shaft for right-handed archers). If, after completing this test, the bare shaft impact is more than 6 inches (15 cm) to the right (weak) or left (stiff) of the fletched shafts at 20 yards (18 m), you will need to make some modifications to the equipment to achieve a better tune. Follow the suggestions on how to better match the arrow to your bow in the “Adjustments Within the Bow and Arrow System” section on page 10.
Proper clearance is absolutely essential for optimum grouping, consistency and accuracy. This is especially true with ultra-light weight arrows like the UltraLite aluminum, the A/C/E and A/C/C HyperSpeed shafts.
After you have performed the Bare Shaft Planing or Paper Tuning Arrow Test, it is a good idea to check for adequate clearance. To check for clearance, use dry powder foot spray, dry deodorant spray or similar product, applied to the last quarter of the arrow shaft, fletching, arrow rest assembly and sight window near the arrow rest. Do not disturb the powder sprayed on the arrow and
Porpoising
Nocking point too low* Nocking point too high*
This tear indicates a low nocking point. To correct, raise the nocking point 1/16" (1.6 mm) at a time and repeat the proce- dure until the low vertical tear is elimi- nated.
This tear indicates a high nocking point, clearance problem, or a very weak arrow if you are using a release aid. To correct, lower the nocking point 1/16" (1.6 mm) at a time until the high tear is eliminated. If, after moving the nocking point a few times, the problem is unchanged, the disturbance is most likely caused by a lack of clearance or by an arrow which is too weak (if using a release aid). To identify a clearance problem, check to see if the arrow fletching is hitting the arrow rest. (See “Clearance” on page 5.)
CR - If no clearance problem exists and you are using a mechanical release, try:
This tear indicates a stiff arrow reaction for right-handed archers using finger release (RF, CF). Left-handed finger release archers will have an opposite pattern. This is an uncommon tear for right-handed compound archers using a mechanical release (CR). However, it can occur and generally indicates that the arrow rest position is too far to the right or that there is possible vane contact on the inside of the launcher rest.
This tear indicates a weak arrow reaction or clearance problem for right-handed finger release (RF, CF) archers. Left-handed finger release archers will have the opposite pattern. For right-handed compound archers using mechanical releases (CR), the left tear is common and usually indicates a weak arrow reaction and/or clearance problem. If a high-left tear exists, (see next tear illustration) make sure you correct the nocking point first before proceeding further.
1.Check for Clearance (See page 5). 2.Decrease bow weight/peak bow weight.
This tear shows a combination of more than one flight disturbance. Use the procedures that apply to the tear pattern for your style of shooting, and combine the recommendations, correcting the vertical pattern (nocking point) first, then the horizontal. If you experience a tuning problem (especially with the nocking point location) and are unable to correct a high/low tear in the paper, have your local pro shop check the “timing” (roll-over) of your eccentric wheels or cams.
For archers using release aids, it may, in some cases, be necessary to apply adjustments opposite from those described. The type of arrow rest and release aid combination used can alter the dynamic flex of the arrow to produce tear patterns contrary to those indicated (although it is uncommon). Once you have achieved a good tune at 4 to 6 feet (1.2- 1.8 m), move back 6 feet (1.8 m) more and continue to shoot through the paper. This ensures that the tune is correct and that the arrow was not just in a recovery position when it passed through the paper at the first distance.
until you achieve the best possible vertical impact line of arrows. If the vertical line widens, go back to your original arrow rest position and move it 1 / 32 " (.8 mm) in the opposite direction. If the vertical line narrows, continue (^1) / 32 " (.8 mm) adjustments in that direction until you achieve the straightest line possible. CF archers using cushion plungers should make the necessary arrow rest adjustments and then try a second tuning adjustment, the cushion plunger spring tension. Increase or decrease spring tension 1/8 of a turn at a time. Again, if the vertical line becomes wider, return to the original spring tension setting and make 1/8 turn adjustments in the opposite direction until you achieve a narrow vertical impact line.
RF archers should make cushion plunger spring tension adjustments only, increasing or decreasing the spring tension 1 / 8 -turn at a time. If the vertical line becomes wider, return to the original spring tension setting and make 1 / 8 -turn adjustments in the opposite direction until you achieve a narrow vertical impact line. Do not move the in/out position of your arrow! The in/out position of your arrow to the centerline of the bow has already been established in the preliminary equipment setup.
You may have heard people say, “If your arrows group well at 20 yards, they will group at any distance,” or, “If your arrows group at long distances, they will group at short distances.” In some cases, neither statement is true. There may be a minute disturbance in the equipment
Fig. 13 Up-Down Impact
Left-Right Impact
Many times it is not possible to shoot long distances when your equipment needs to be tuned. The following method results in a very good equipment tune at short distances. Use this tuning method after you have completed one of the basic bow-tuning methods—either the Bare Shaft Planing or Paper Tuning Arrow Test. Start at approximately 12 to 15 yards (meters) from the target. Use a 40 cm or 60 cm target face and place it with the face side in so you are shooting at a plain white target.
Using fletched arrows only, shoot approximately 6 to 8 arrows along the top edge of the target face. This step determines if your nocking point is correct. See Fig. 13.
Normally, small tuning problems show up at close range, because the arrow has its maximum vibration at short distance. This test assists you in identifying these arrow flight problems and makes it possible to make finer adjustments than with the previous tuning procedures.
If you are unable to consistently hit the top edge of the target face, there is probably a small tuning disturbance in the equipment. To correct, make a 1 / 32 " (.8 mm) nocking point adjustment either up or down and shoot again. Continue making nocking point adjustments in (^1) / 32 " (.8 mm) increments (no more than 1 / 32 " (.8 mm) at a time).
If your arrows are hitting the top edge of the paper more consistently and you are achieving a straight, horizontal line of arrows across the top of the paper, you are correcting the disturbance. If the horizontal line of arrow impact is widening, go back to your original nocking point position and start making 1 / 32 " (.8 mm) nocking point adjustments in the opposite direction. This will provide you with the correct nocking point position.
Once you have achieved the straightest horizontal line of arrows that your ability will allow, you are ready to tune for left/right arrow impact. Shoot 6 to 8 arrows at the left edge of the paper in a vertical line. See Fig. 14.
To improve the left/right impact for CR and CF archers, move the in/out position of your arrow rest. This is done to compensate for the effect of the eccentric wheel. The offset of the eccentric wheel on compound bows does not always compensate for the degree of natural torque generated in the bow. The wheel often torques or leans over slightly as it reaches the full draw position. This is common and is nothing to be concerned about. At full draw, the “limb center” you started with in the preliminary setup may not really be the true balanced center. Therefore, through some trial and error, you must locate the best in/out position for the arrow to obtain maximum accuracy. Make a 1 / 32 " (.8 mm) adjustment either in or out and shoot again. Continue making 1 / 32 " (.8 mm) adjustments
If you are having problems tuning your bow, you will need to make some modifications to your equipment to achieve a better tune. Here are some suggestions:
Virtually all compound bows, as well as some recurve bows, have an adjustable draw weight. If your arrow reaction is too stiff, increase the draw weight. If your arrow reaction is too weak, decrease the draw weight.
Bowstring “weight” can have a significant effect on arrow spine. Increasing or decreasing the number of strands in the bowstring can influence the arrow's dynamic spine enough to require a shaft size change of one full size weaker or stiffer. If your arrow reaction is too stiff, decrease the number of strands in your bowstring. If your arrow reaction is too weak, increase the number of strands. Serving weight (center serving) can also produce the same effect. For example, monofilament center serv- ing will cause the arrow to react stiffer than lighter weight nylon center serving. Simply changing from a metal nocking point to a “tie-on” nocking point can have a noticeable effect on arrow spine, due to the weight difference between the two styles of nocking points.
The bowstring is a critical part of your technical equipment. If you have a very difficult time tuning your bow, the problem could be the bowstring. An incorrectly made bowstring can produce a tension imbalance in the strands of the string causing some strands to be looser than others. This imbalance forces the string to load and stretch at different rates, creating an inconsistent arrow launch which greatly decreases accuracy. If a problem exists, and tuning procedures don't seem to be working, try changing the string and retuning.
X10, A/C/E and A/C/C, & Beman ICS arrows can be tuned by using various point and/or insert weight com- binations. External component systems use weight com- binations of point plus outsert. Aluminum arrows can be point-weight-tuned by using 7%, 8% or 9% F.O.C. NIBB points. If your arrow is too weak, go to a lighter insert/ point. If your arrow is too stiff, try a heavier insert/point. Continue to change insert and/or point weight within the acceptable balance point range (7-16% F.O.C.).
For recurve bows, another way of altering arrow spine is with the brace height. By increasing or decreasing the distance from the bowstring to the pivot point of the grip, the dynamic spine of the arrow can be made slightly weaker or stiffer. Increasing brace height will make the arrow shoot weaker, and decreasing brace height will make the arrow shoot stiffer.
Brace height affects arrow spine by increasing or decreasing the amount of energy delivered to the arrow at the moment of release. Raising the brace height (shortening the bowstring) compresses the limbs, increasing stress (prestress or preload) in the limb ma- terial. The more preloading of the limbs, the greater the actual bow poundage at full draw. The reverse is true when lowering brace height. A lower brace height (lengthening the bowstring) reduces the prestress in the limbs and reduces bow weight at full draw.
However, raising brace height produces some small loss in arrow velocity as the slight increase in draw weight does not equally compensate for the reduction in the bow's “power stroke.” When the power stroke is reduced, the amount of time the arrow stays on the bowstring is also reduced, in turn, decreasing the length of time the arrow has to absorb the bow's energy.
Although you may note a small loss in velocity when increasing brace height, do not let speed be the deciding factor when selecting the best brace height for your bow. As is often said, “Better to have a slow bull's eye than a fast miss.” Adjusting the brace height on a compound bow is often overlooked as a tuning adjustment. This is because the changes in brace height will change the draw length and draw weight possibly requiring additional adjustments. Nevertheless, finding the correct brace height for your compound (usually higher than the manufacturer’s setting)
bance within the bow and arrow system. To correct, see the section on Clearance on page 5 or the Fine Tuning and Micro Tuning sections on pages 12-14.
Fig. 18 illustrates why you may have problems with close distance grouping while long-distance groups are good. When an arrow is shot, it is at its maximum bending as it leaves the bow. As the arrow travels further, the amount of flexing reduces (dampens). If the flexing reduces, then so does the magnitude of any original disturbance. The example shows that the arrow has some disturbance and close range grouping is poor, although the arrow stabilizes at longer range and provides acceptable groups. Micro disturbances and clearance problems usually cause these disturbances. Fig. 19 shows the path of the arrow when it leaves the bow without any disturbance. This is the path you are trying to achieve in the Fine Tuning and Micro Tuning processes.
6 4 " 7 3 / 4 " – 9" (19.7 cm to 22.9 cm) 6 6 " 8 " – 9 1 / 4 " (20.3 cm to 23.5 cm) 6 8 " 8 1 / 4 " – 9 1 / 2 " (21.0 cm to 24.1 cm) 7 0 " 8 1 / 2 " – 9 3 / 4 " (21.6 cm to 24.8 cm)
The field points should be as close in weight as possible to the weight of the broadheads. Because it is necessary to first establish a good group with field points, broadhead tuning can be done only after acceptable tuning has been established with field points.
Set up a suitable broadhead target at a distance of 20 to 30 yards. Using a set of field-tipped arrows that have been tuned with your bow, shoot a group of 3 or 4 arrows into the target. Take care to shoot as good a group as you are capable.
Using identical arrows tipped with broadheads, shoot a group of 3 or 4 arrows into the target. Use the same aiming spot that was used for the field points.
The shot group is the key. If you are content you have shot a respectable group based on your ability, then compare the position of the two groups. Make the adjustments listed below to your setup and shoot both groups again. Keep adjusting and shooting until both groups (field points and broadheads) group in the same area.
See Fig. 20 below and adjustments on next page.
can, in many cases, greatly improve consistency and grouping and should be considered as a fine tuning adjustment.
The chart on the previous page shows the full range of brace height adjustments for most modern recurve bows. Changes within the brace height ranges shown can affect arrow spine as much as changing the arrow point and/or insert weight approximately 20 grains (1.3 grams). Remember, it is best to shoot your bow at its smoothest and quietest setting, (although most recurve bows perform well at two brace height settings). Easton does not suggest an extreme range of brace height. The chart offers a range wide enough to create a “between” size arrow spine.
If, after trying all of the tuning procedures listed, you find your arrows are still too weak or too stiff to fly properly, choose a different arrow size and retune.
In general terms, broadhead tuning is done by first shooting a group of arrows with field points into the target, and then by shooting a group of arrows with broadheads. The two groups are compared and the appropriate adjustments are made.
CAUTION: Never shoot unfletched shafts with broadheads—flight is extremely erratic and dangerous!
Lower Nocking Point
Raise Nocking Point
Weak Spine Reaction (Adjustments are for right- handed shooters. Reverse for left-handed shooters.)
Stiff Spine Reaction (Adjustments are for right- handed shooters. Reverse for left-handed shooters.)
= Field Point Group
= Broadhead Group
Multiple Adjustments
Remember – make only one adjustment at a time.
Adjust the nocking point 1 / 32 " (.8 mm) either up or down. Shoot another two groups and plot the arrows in the same manner as described on page 12. For future reference, be sure to write down your bow adjustment on each arrow group you plot. Compare the groups to determine if the high and low arrow impact has improved or is worse. If it has improved, make another adjustment of 1 / 32 " (.8 mm) in the same direction and shoot another two ends. If the high and low arrow impact is worse, go back to the original setting and make the same adjustment in the opposite direction. Continue this process until you achieve the most consistent group elevation.
CF and CR shooters can adjust the left/right position of your arrow rest approximately 1 / 32 " (.8 mm) either in or out. Shoot two groups and plot the arrows. Be sure to indicate your bow adjustment on each plotted arrow group. Compare the groups you just shot and determine if they are getting better or worse. If the groups improved, make another adjustment of 1 / 32 " (.8 mm) in the same direction and shoot another two ends. If the groups are worse, go back to the original setting and make the same adjustment in the opposite direction. Continue this process until the best possible groups have been achieved with this single adjustment.
After left/right adjustment of the arrow rest or cushion plunger, CF shooters can adjust the spring tension of the cushion plunger 1 / 8 - to 1 / 4 -turn weaker or stiffer and continue the procedure, making 1 / 8 -turn adjustments at a time to achieve a finer tune.
Remember, RF archers should adjust the cushion plunger pressure only, increasing or decreasing the spring tension 1 / 8 -turn at a time. Do not move the in/out position of your arrow!
Carefully examine the arrow grouping patterns you plotted. Note the different shapes of the groups and how the adjustments altered the arrow impact and size of the groups. Examine each arrow by its number. Take careful note of any arrows that did not group consistently with the other shafts. You will probably want to mark these shafts so you will know not to use them in competition.
You may find an arrow that does not group well with the other arrows in the set. Examine it before you discard that arrow or retire it from competition. Sometimes a problem is easily identified. If a shaft is cracked or dented it should be discarded.
Some arrows may seem fine, but they may have problems which are not obvious and can cause the arrows not to group well. The following list includes the common arrow problems, many of which can cause tremendous impact variations.
Arrows must be straight for tight grouping. Easton rec- ommends straightness within 0.004" for best grouping.
There are several ways to check nock straightness, in- cluding commercially available nock gauges and broad- head spinning wheels.
It is possible that one nock in the set may be turned more than the others. A clearance problem results if the nock is rotated too far, forcing the fletching into the arrow rest when shot.
If the fletching becomes even slightly detached from the shaft, the arrow will not group with the others. In fact, the arrow may not even hit the target past 30 yards (meters) if the back of any fletch is slightly loose! Fletching that is slightly damaged will not usually affect arrow grouping unless you shoot a hard or rigid vane. Care should be taken to examine hard vanes each time you shoot to ensure that no vanes are damaged. If the rear of any hard vane is bent, it will produce a rudder effect, causing large deviation in impact.
Many archers are not aware of this potential problem. Points must be properly installed with Easton's hot melt adhesive fully coating the entire length of the shank of the point or insert. Carefully follow the instructions on point/insert installation which follow later in this Guide. Easton recommends only Easton's hot melt adhesive. If you are using another hot melt ferrule cement, it may be too brittle and may fracture when the arrow impacts hard target butt materials. If the cement fractures or is improp- erly applied, it can result in a separation between the point/insert and the shaft. When the arrow is shot, the separation of the bond between the shaft and point can produce a secondary vibration which in turn affects the arrow’s natural vibration and accuracy. To test for point vibration, simply hold the arrow near the fletching and lightly tap the point on a table, or drop the arrow on a hard floor from a height of one foot. If you hear a buzzing sound, the point/insert is probably loose. Heat and pull out the point/insert and properly reinstall per Easton's instructions on page 19.
Arrow weight is an important consideration for the serious tournament archer and should be checked if you have arrows which consistently impact a little high or low of your group.
A matched set of arrows should have no more than a three grain spread between the heaviest and lightest arrows in the set. Top tournament archers frequently match their arrows to one grain or less.
Micro Tuning adjustments are similar to Fine Tuning and are designed to produce optimum grouping at all distances.
Make no more than a 1 / 32 " (.8 mm) change in nocking point height either up or down. Shoot two more ends and record the distance between the highest and lowest arrow. If the combined distance between the last two groups is less than the combined total of the first two groups, you are making the correct adjustment. Con- tinue to make 1 / 32 " (.8 mm) nocking point adjustments until you achieve the shortest possible distance between your high and low arrows.
If after several nocking point adjustments, you notice the group height starting to open back up, you have probably gone too far in the adjustment and need to go back to where you had the best setting.
Once you are satisfied with the impact height of your arrows, you will need to correct the left/right impact. Continue shooting groups of 8 to 10 arrows. Shoot two ends and measure the distance between the furthest left and furthest right arrows for both ends.
For compound archers (CF and CR), move the in/out position of your arrow rest 1 / 32 " (.8 mm) in either direction. Shoot two more groups and again measure the distance between the furthest left and right arrows. Compare these two ends against the previous two ends. If the total width of the grouping pattern has reduced, you are making the correct adjustment. If the group becomes wider, go back to your original setting and move the rest 1 / 32 " (.8 mm) in the opposite direction and resume the test. Continue these adjustments until you have achieved the tightest possible grouping at that distance. CF archers using cushion plungers should make the in/out adjustments first until you have achieved the tightest left/right impact possible. Then, you can use the cushion plunger spring tension the same as described for recurves to fine tune your arrow impact.
Recurve archers (RF) should adjust only the cushion plunger spring tension, not the in/out adjustment. Make adjustments to the cushion plunger spring tension in 1/8 turn increments only. Follow the same instructions as for compound bows by first shooting two groups and measuring the furthest left and right arrows. Make the first spring tension adjustment either stiffer or weaker and shoot two more ends. Again, if the group becomes wider, go back to the original setting and make an adjustment 1/8 of a turn in the opposite direction.
Once you have completed the long distance tuning, move up 20 yards (18 m) and work on the left/right impact again, making the same adjustments as at the previous distance. It should not be necessary to adjust the nocking point, only the adjustments for left/right grouping. After you have completed this distance, move 20 yards (18 m) closer and repeat this test again for left/right impact only.
Continue this process until your last distance is approximately 20 yards (18 m) from the target. You may find that as little as 1 / 8 of a turn on the cushion plunger or a 1 / 32 " (.8 mm) in/out adjustment (for compound bows) can have a noticeable effect on short distance grouping. It is essential to continue testing and tuning in 20 yard ( m) increments. This way, you will know that your equipment can perform well at any distance when shooting competition.
This same fine tuning procedure can be done with brace height for both compound bows and recurves. Make brace height adjustments in approximately 1 / 32 " (.8 mm) increments and plot the arrow groups. After completing this procedure, you should find a combination of adjustments that will either slightly or significantly improve arrow grouping.
Install all accessories on your bow before you start any bow tuning procedures. An essential part of your equipment is a good quality set of arrows. Adjustments made to the bow, changes in bow components, or alterations in shooting form can affect the tune or your equipment. Remember, you and your equipment share a unique relationship and are totally integrated. Any change to either will produce varying effects. Change only one variable at a time when tuning. If, after trying all of the tuning adjustments outlined in this Tuning Guide, your arrows still do not fly true, it may be necessary to change your arrow size to a stiffer or weaker shaft and retune.
Some shafts are fitted with components that fit over the outside of the shaft. To accommodate this, the outserts and one-piece points must be larger in diameter than the shaft. Therefore, all Correct Arrow Length calculations allow for at least 1 ⁄ 2 " clearance from the back of the One- Piece Point or Standard Adapter to the most forward part of the arrow rest (as indicated by the diagrams). This prevents any disturbance to the arrow caused by the outsert as the arrow is drawn or released.
NOTE: Beginners with recurve bows may want to add an extra 1 ⁄ 2 "-1" to their arrow length so that, as they become stronger and their shooting technique improves, the arrow will not be too short.
Correct Arrow Length
(^1) / 2 " clearance from the back of the 1-Piece Point to the most forward portion of the arrow rest
Correct Arrow Length
(^1) / 2 " clearance
(^1) / 2 " clearance
Correct Arrow Length
(^3) / 4 "
1 1 / 8 "
1" broadhead clearance
1 Correct Arrow Length / 4 "
Correct Arrow Length is measured from 1 / 4 " beyond the far side of the bow.
Correct Arrow Length for hunting/field arrows equipped with Point Outserts and broadheads or screw-in points shot from bows WITH OVERDRAWS AND CUTOUT sight windows.
Correct Arrow Length for target arrows with One- Piece Points shot from ALL TYPES of bows (with or without cutout sight windows and with or without overdraw).
Correct Arrow Length for all arrows shot from bows WITH CUTOUT sight windows (no overdraws).
Correct Arrow Length for hunting arrows shot from bows WITHOUT CUTOUT sight windows (or not cutout enough for broadhead clearance). NOTE: On bows without cutout sight windows the broadhead cannot be pulled “into the bow.” It is necessary, then to provide enough broadhead clearance in front of the bow when the arrow is pulled to full draw to prevent the broadhead from bumping against the bow.
Correct Arrow Length is measured from 1 1 / 8 " in front of the most forward part of the arrow rest.
Correct Arrow Length is measured from 1 1 / 8 " in front of the most forward part of the arrow rest.
For target points Correct Arrow Length is measured from 3 ⁄ 4 " in front of the most forward part of the arrow rest.
1 1 / 8 "
For hunting arrows on bows without cutout sight win- dows your broadhead should have at least 1" bow clear- ance past the far side of the bow. Have someone mark an extra long arrow while you’re at full draw about 1" beyond the back (far side) of the bow (see figure 22).
Correct Arrow Length 1" Clearance
Correct Arrow Length for hunting arrows with broadheads shot from bows WITHOUT CUTOUT sight windows (or not cutout enough for broadhead clearance).
Remember that your Correct Arrow Length is measured to the bottom of the nock groove and includes the small distance that the nock base extends beyond the nock taper. Therefore, your shaft cut length is slightly shorter than your Correct Arrow Length.
After determining Correct Arrow Length follow the steps below. Note: Carbon shafts of all types must be cut carefully to prevent splintering of the carbon (graphite) fibers. Never use rotary tube cutters, hack saws or other meth- ods that can damage the shaft or leave a rough cut. Always wear a NIOSH approved dust mask and safety glasses when cutting arrow shafts!
Cut through (^1) / 3 of the O.D. of shaft
Cutoff Wheel
Shaft
Adjustable shaft support
Wheel Rotation
The Easton Cutoff Tool is designed to cut all tubular arrow material. The precision motor turns a thin abrasive cutting wheel for an exceptionally burr-free cut on aluminum and can prevent splintering of carbon fibers when cutting carbon shafts.
Shaft Rotation
Deburr no more than 1 / 4 of the wall thickness
High strength aluminum core tube.
Deburr no more than 1 / 4 of the aluminum wall
45 ° Chamfer
Deburr just enough to remove burr.
MATERIALS NEEDED FOR INSTALLATION OF CARBON COMPOSITE INSERTS
For an accurate, high-strength installation, be sure the shaft ends are cut square. Follow the shaft cutting instructions carefully.
When removing an aluminum insert, first thread an RPS Field or Target Point into the insert.
CAUTION: Do not overheat the component or the shaft.
Carbon Composite Inserts can be removed by slowly heating the shaft (aluminum shafts only) and breaking down the bonding adhesive with heat. CAUTION: Do not overheat the shaft!
Unless your fletching jig has an adjustable nock indexing feature, you may choose to fletch your arrows with the nocks temporarily installed. After fletching, properly index and bond the nocks so that your style of vanes clears your particular arrow rest. NOTE: If the nocks are installed without adhesive the UNI and Super UNI Systems allow you to rotate the nock to obtain proper alignment at any time.
CAUTION: Do not dip shafts with UNI Bushings or Super UNI Bushings in lacquer or use petroleum solvents to clean the fletching surface.
See Installing Nock Systems later in this guide.
ALUMINUM/CARBON
COMPONENT
INSTALLATION
EQUIPMENT AND MATERIALS NEEDED FOR INSTALLATION OF POINTS AND ALUMINUM INSERTS
The instructions that follow can be used for either One-piece Points or for aluminum inserts. For aluminum inserts, screw a point into the insert before you begin installation. After cutting your A/C* Shaft to length as described, follow the point installation procedure carefully to prevent overheating the point. Overheated points can destroy the shaft’s epoxy bond between the carbon and the aluminum tube. Use only Easton hot-melt adhesive.