Tuning a Bow: Part 2

This is part two of our blog series, “Tuning a Bow,” where we provide you with everything you need in order to get your gear ready for hunting season. In part one, we covered topics like inspecting your string and cable, as well as installing a peep sight. Click here to read more. We’ll round off the process with the final touches to fine tune your archery gear.

Choosing the Right Fletching

Not so long ago, bowhunters could only choose between feather fletching or soft, flexible plastic vanes. They were long and thick, but could be configured in an offset, helical or straight position. Today, the options have expanded and are designed to offer maximum speed and accuracy. Specialty vanes such as Blazers or Nap Quick-Spins have become the standard for hunters, regardless of what broadhead or rest they’re paired with.

An important part of tuning a bow includes choosing the right fletching.
An important part of tuning a bow includes choosing the right fletching.

If you are not shooting tight groups with a broadhead, arrow stabilization may be a cause. A faster spinning arrow equals better stabilization, and choosing different vanes can help with that. The stiff, urethane Blazer vanes provide outstanding arrow guidance and are rigid enough to withstand repeated shooting through capture-style rests, such as a Whisker Biscuit. For most setups, if you are selecting new arrows and vanes, consider Blazers for whatever broadhead or rest you use.  

Find the Front of Center

Front of center (FOC) is not the center of the arrow, but the location of where the arrow balances after components (nocks, fletchings, inserts, broadheads) are installed. Knowing the FOC will assure you have a good compromise between stable arrow flight and arrow range, and aids in choosing the proper broadhead grain. Here are the steps to finding the FOC:

1. Install all components and measure the arrow’s overall length – from the throat of the nock to the tip of the broadhead. For example, let’s say this measurement is 29 inches.

2. Find the balance point. This is where the arrow balances perfectly. Mark it and measure from the throat of the nock. (Example: balance point = 17 inches)

3. Divide the overall length by two to get the actual center of the arrow. (29 / 2 = 14.5)

4. Subtract the center of the arrow measurement from the balance point. (17 - 14.5 = 2.5)

5. Divide the resulting number in Step 4 by the arrow’s overall length.  (2.5 / 29 = .0862)

6. Multiply the resulting number in Step 5 by 100. (.0862 x 100 = 8.62)

In this example, the FOC would be 8.62 percent. If your FOC falls outside of the optimal range of seven to 11 percent you will want to adjust the weight of your broadhead accordingly. Use a heavier broadhead if the FOC is less than seven percent and a lighter broadhead if it is more than 11 percent.

Spin Test Arrows

An important part of bow tuning is checking the weight and straightness of your arrows. It doesn’t matter if you selected heavy or light ones, Blazers or feather fletching, or mechanical or fixed-blade broadheads – your arrow setup should be tested to make sure they spin true. You should perform this test every time you install a broadhead because each time you screw one into the arrow’s insert, there’s a possibility it will seat differently. To make sure you are shooting a straight arrow, follow the steps below.

1. If you have not yet installed your broadhead and other arrow components, do that first.

2. Spin test each arrow using a flat surface that allows the broadhead and fletching to overhang or use an arrow spinner like this DIY one we built for under $10.

3. Roll the arrow along the surface and watch for any wobbling. If the arrow seems to be wobbling where the broadhead meets the shaft, remove the broadhead, heat the insert to soften the glue and thread on the broadhead again to re-align the insert. If it continues to wobble, it’s likely the shaft is bent or the insert is glued in crooked. If the arrow wobbles on the nock side, be sure the nock is aligned. Check to be certain that extra glue around the fletching is not causing the arrow to be out of balance.

It's important to spin test your arrows with broadheads attached to uncover any issues.
It's important to spin test your arrows with broadheads attached to uncover any issues.

Paper Tuning

Paper tuning a bow will ensure you are using the right arrows, have no clearance issues and your rest is aligned properly. By shooting through a sheet of paper, you can analyze the tear your arrow leaves and make adjustments as needed. Below is a paper tuning guide:

1. Secure a sheet of paper – wax paper, newspaper or gift wrapping paper work well – to a picture frame or a piece of cardboard with a 24” x 24” window cut out of it. You want the paper to be positioned shoulder height, four to six feet from your shooting line. Place a target at least four feet behind the paper to stop the arrow. Be sure the arrow can pass completely through the paper before it hits the backstop.

2. Shoot an arrow through the paper and observe the tear that’s made and compare it to the examples below.

Perfect Arrow Flight Tear: A tear like the shape above shows the arrow is stable as it’s passing through the paper. Shoot a few more times to be sure your bow setup is perfect.

Low vertical tear: If you get a tear like this when paper tuning, your nock is likely too low. Raise it in 1/16-inch increments until you are getting a tear indicting perfect arrow flight. If adjusting the nock point does not fix the issue, have your local bow shop check the timing of your bow’s cam(s).

High Vertical Tear: This tear can be the result of multiple issues, such as too high of a nocking point, an arrow making contact with the rest or using an under-spined arrow. Check the arrow fletching for evidence of contact with the rest. If you believe this is the cause, rotate the arrow’s nock a quarter-turn and test again until the tear improves. If adjusting the nock doesn’t help, start moving the rest horizontally toward the riser in 1/64-inch increments. If your arrow is still making contact with the rest, you may need to replace the fletching with lower profile vanes.

If your arrow is not making contact with the rest, and you are still seeing a high vertical tear, lower the nock point in 1/16-inch increments until you are getting a perfect arrow flight tear. If that does not fix the issue, have your local bow shop check the timing of your bow’s cam(s).

Left Horizontal Tear: If you are getting this tear and are a right handed shooter, move your rest right (towards the riser) in 1/64-inch increments, until the tear is perfect. If that does not correct it, try a stiffer shaft.

Right Horizontal Tear: Make the adjustments needed to fix a Left Horizontal Tear in the opposite direction (move the rest to left if you are a right handed shooter).

Diagonal Tear: An arrow making a tear diagonally is a sign of multiple issues. First, work on the vertical tear issues above and then make movements to the rest until you are making a perfect tear in your paper tuning tests.

If you are observing inconsistent tears throughout the paper tuning process, make sure your form is consistent. Once you are shooting bullet holes through the paper, it’s time to sight-in using field points.