This is the Hamskea 3rd axis tool i mentioned. In my opinion it is worthy of owning at a decent price point
Prior to three years ago I had no idea what 2nd and 3rd axis on a bow sight was. When someone first told me about it I thought to myself, “like that matters”. Well, I’m here to tell you that it does matter and becomes especially important when you’re shooting at any angle opposite of flat ground. Most are familiar with a sight bubble and think as long as that bubble is where it needs to be at the shot you will put that arrow right where you’re aiming. While that may be the case when shooting targets in your back yard it becomes much more apparent it’s not the case when shooting in the mountains or on a 3D course with cross hill angles.
2nd axis is pretty straight forward and easy for you to set with minimal effort. What you’re doing is making sure that the bubble in your sight matches your riser when your bow is perfectly plumb. There are a couple ways to achieve this and I’ll explain how I do it. Put your bow in a vice, a bow vice is preferable as you won’t risk damaging your limbs or riser. You can use a 4’, torpedo, or string level to make sure your bow is plumb in both directions once in the vise. I find it easiest to clip a string level on and plumb it that way and then check it with a 4’ level spanning both limbs. Not all bow sights come with second and third axis adjustment so if you don’t have it, don’t worry, you can still get it right. From here, if your sight has second axis adjustment, all you have to do is make sure the bubble on your sight is reading in the middle of the sight glass. If your sight doesn’t have second axis adjustment then you can simple unscrew the top or bottom screw on your sight, slide some Teflon shims behind it and retighten the screw. Add as many shims as needed to get the screw tight while keeping that bubble where it should be.
Sights such as HHA, Spot Hogg, Sword, MBG, and many others have both 2nd and 3rd axis adjustment. Thus, the higher price point.
Imagine taking a nock out of an arrow and clicking it on the string. With the knock facing forward, like it shouuld if it had an arrow on it; spin the knock left and right. That simple explanation is what your third axis is. Every person and every bow puts different torque on the riser while at full draw, that’s why the third axis is so intimate. You’re personalizing your sight to how your bow reacts when you pull it back. Third axis adjustment takes a little more patience to set and is easier with the proper tools. I picked up a Hamskea Third Axis tool and never looked back. This tool clips to you sight bar, or riser, and helps with the process immensely. Some sights, such a Spot Hogg, have wires in the housing which allows you to do this without the tool I mentioned. Some people are able to also do this process with their sight pins, but if you’re going to go that route make sure your pins are perfectly in line. You can use a door jamb, if it’s plumb, a string and plumb bob, or draw a vertical line on the wall and still achieve the same results for setting your third axis. Be sure you are using the same grip you use when shooting your bow everyday while doing this or your results won’t always come out the same. What you want to do is; come to full draw, bend at the waste and try to achieve an angle of 30 degrees or more, up or down doesn’t matter. Look at the vertical wire on your sight, or rod on the Hamskea tool, while at full draw and make the bottom and top line up with the line you’re using as a plumb reference. Once these two things are aligned check the bubble on your sight. If the bubble is still in the center of your sight glass then your third axis is right on, if not then you have some adjusting to do. Again, not all sights will have third axis adjustment and its okay if yours doesn’t. If you don’t have a sight with the adjustment you will have to loosed both sight screws and slide shims either in the front or the back of the dovetail, evenly, until your bubble is true when repeating the above process.
Your probably thinking, why is this important, were not splitting atoms here, were shooting animals. It’s important for a couple reasons. The first reason is that no matter what plain you’re shooting on, up, down, sideways, you want that bubble to read true. Once these are set and your bubble reads true then you know you are perpendicular to the world at that moment, or your bow is anyway. You should experiment with this yourself, go out and shoot diagonal down a steep slope. Set your 3rd axis and go back to that same hill and shoot that exact shot again. You will find that at a range of 40 yards you can be anywhere from 4-6” left or right of where you were aiming prior to setting it, and right on once its set. As Will Farrell would say, “its mind bottling”. Yes bottling, not boggling. The reason you were off left or right is because your bubble was lying to you. Your bubble said, “I’m going to ignore the cant in your bow right now and tell you you’re level” when in fact you are not. The second reason it’s important is because the further you shoot, without it set, the further the miss. A clean miss sucks but a lethal wound without recovery of the animal is worse. I’m not preaching from my ethical high horse, because I have experienced both. A good friend of mine took a 73 yard shot at a quartering away 340” bull last year, only to miss him clean left. He is an excellent shot and can, and has made shots like this in years past. What he didn’t account for was how steep the angle was and the fact that his third axis was not set. You live and you learn, but I’m not sure I could sleep at night missing such an opportunity at a trophy class animal on an over the counter tag.