How many of you out there are hunters? I'm sure the vast majority of you out there are hunters and probably whitetail deer hunters at that. Then, how many of you hunt from tree stands? Probably again (going on assumption) that the vast majority are hunting from tree stands. So here's the big question, how many of you level your bow sight through the 3rd axis to ensure your level when you shoot downward at that big buck you have been tracking all year? I'm going to guess that the hardcore bow hunters will do this, but the others probably not much. Just get your bow setup from the shop and move the sights around a little bit perhaps.
The third axis is extremely important in hunting situations and in 3d shoots, so what is this 3rd axis? This 3rd axis is when you are in your treestand or are in a 3d shoot and need to tip your body and you are now shooting not on a horizontal plane, but at a upward or downward angle. Such as bending at the waist to shoot at a deer 25 yards out from a treestand 20ft up in the air. This is now what is called the 3rd axis and the sight potentially goes not level with the bow. What then happens is you now are aiming for the vitals, but your arrow hits too far back or too far forward. This could be huge when shooting at the deer you have been tracking all year or at a 3d shoot and you need that 10 or 12, but hit an 8 instead because of the extreme angle.
Now, how do we fix this issue.
To resolve this issue we need to look at getting the bow in a bow vise, then level the bow first off. I typically use my bowstring level to get the bow level both side-to-side and front-to-back. So at this point we can now level the 1st and 2nd axis's of the sight. The first is the front-to-back, I take a small level and then put it on the bow sight itself and ensure that the sight is level, if not I adjust as required per the instructions that came with my sight for the 1st axis.
For the 2nd axis, I then look at the two levels on my sight and bow string. If they are out of alignment, I then adjust my sight to being level and matching my bowstring level. At this point, the sight should be level to the bow in the fashion of just being straight up. Additionally, for most bow hunters, this amount of leveling is fine and with hunting from a stand in a tree, this would be good enough.
Now, once you get into 3d shoots and want to make better shots on your animals while hunting you are going to want to level your 3rd axis to ensure your sight stays level with your bow. Now, there are multiple ways there are do accomplish this, though since it is just myself, I attach my bow to my vise and level just like before, then I tip the bow forward as far as my vise allows, about 45 degrees. Then, there is a 3rd axis that (the best to describe is) swings the sight forward and backward. This is the third axis, swing the sight in / out until the bubble is level. Then tighten it up.
At this point, your sight should now be leveled with the bow vertical front/back and side/side, then when shooting on an angle your sight should be level to the bow at the minimum of a 45 degree angle. So overall, your shots at any angle during the shoot or when shooting at your target animal should be spot on and not need you to hold the bow off target to compensate. Though, this is just leveling your sight to the bow, you will now need to take the time to practice and shoot on all the different angles to get a good feeling of how your bow reacts to all these different types of shots.
Good luck out there and I hope this helps with understanding why the 3rd axis is important and how to get that dialed in!!