The 3rd Axis
by Paeton Keller
What is the 3rd Axis?
On most modern archery sights, engineers have added the feature of the 3rd axis adjustment. This feature can be key for those wanting to achieve maximum accuracy in all hunting scenarios. However, many hunters are unaware of what the “3rd axis” is, and how it can help them become more proficient at their craft.
The 3rd axis setting on sights that have this feature is an adjustment that allows an archer to align the sight bubble level to be perpendicular to the path of the arrow. Not all sights are the same. Pictured is an Axcel target style sight. On this sight, the axis on which the sight pivots is indicated by a 3rd axis label. Other sights may have the 3rd axis adjustment on the extension (the bar that connects the bow mount to the vertical adjustment); on other sights, the bubble level itself can be rotated. In all cases, the concept is the same; rotate the bubble level on the sight, so that it is perpendicular to the arrow’s path.
Why is the 3rd Axis Important?
The 3rd axis becomes a factor on shots taken from an incline or decline, and is more crucial the greater the angle or distance. An archer may not notice the effect of a misaligned 3rd axis during normal practice on level ground; however, once the archer begins to shoot up- or downhill, the effect will be more evident. When shooting on an incline, the archer may notice their arrows hitting either high and right or high and left. On a decline, the effect will be opposite; for example, if you are shooting high, left at an incline, then at a decline the arrows will hit high and right. With a properly adjusted 3rd axis, the arrow will impact on center no matter the angle (given proper form and shot execution).
How do I properly adjust the 3rd Axis?
The first step to adjusting the 3rd axis (if your sight is capable of making the adjustment) is to make sure your bow is properly tuned and sighted in. This includes first and second axis to be set (up/down and a level bubble in reference to the ground and the riser) and proper shooting form. A bow that is not properly set up can cause difficulties in creating more variables in the process.
One mistake that many people make in setting the 3rd axis is aligning the bubble level perpendicular to the bow riser. While this can suffice as a starting point, it will generally not be accurate because few archers are able to tune their bow to shoot the arrow straight off of the riser (due to many factors including bow torque resulting from cable guards and archer-induced hand torque). This is why many archer’s pins are offset slightly away from the riser from being in line with the arrow.
Setting the 3rd axis:
- To begin, set the bubble level perpendicular to a hypothetical line that goes from the center of your rest to your pin. By aligning the bubble to the rest, you will take into account the torque applied to your bow during the shot. This is only to get the adjustment close.
- Next, test the 3rd axis adjustment. The preliminary test should be at close distance. Use a level to draw a vertical line on a target. From five yards, shoot an arrow with your bow level. Next, shoot one arrow at a 45-degree decline and another shot a 45-degree incline at the line on the target. The goal is to get all three arrows the same distance from the line you have drawn. The arrows may not land perfectly on the line, but as long as they are all the same distance from the line then you are set. If the arrow shot at a decline is to the left of the arrow shot at level, then rotate the bubble level in the positive direction as indicated by the picture to the left (always adjust in small increments) and repeat the test until all three arrows are perfectly vertical. If the arrow shot at a decline is to the right instead of left, then perform the opposite adjustment or to the negative direction as indicated by the image. When shooting at an incline, an arrow hitting left means that you must move the bubble in the negative direction. If the arrows group to the right at an inclined shot, move the bubble in the positive direction.
- Now, take a step back. With the 3rd axis set at close range, try shooting at distance. Perform your test at the furthest distance that you can get consistent and accurate groups. Shoot on level, and then shoot at an incline and decline. Use the same movements as directed at short range to fine tune the 3rd axis at distance. Remember, a 3rd axis that is not properly adjusted will also cause vertical errors so keep that in mind when fine tuning the 3rd Another factor to keep in mind is that any change to the bow or arrows may cause the 3rd axis to become misaligned. So, after making any changes to your bow, verify and/or adjust your 3rd axis.
Of course, the best way to increase accuracy is to practice!