3rd axis adjustment on your sight
LiteSpeed1 said:
Can someone please explain third axis tuning?
LiteSpeed1:
2ND AXIS
2nd axis on your sight is basically making sure the bubble level
on your sight reads level when the bow is vertical.
This presumes that your string is vertical when the bow is also vertical.
You essentially figure a way to hold your bow vertical (use a bow vise),
and then check to see that your bubble level in the sight is also reading vertical.
If not, then adjust the bubble level with the 2nd axis adjustment,
to make the bubble level on your sight read level, when the bow and bowstring are vertical.
3RD AXIS
Ok, so now we understand what 2nd axis is on your sight.
So, what is 3rd axis?
Remember your sight ring is on a threaded rod?
Well, what if the entire sight ring was mounted on a door hinge?
Yup. What if the entire sight ring could swing like a door?
You could swing the door towards you or away from you.
Well, let's say we swing the door towards you 45 degrees.
The bubble level still reads level, i.e., the threaded rod is still horizontal.
You know what will happen on a steep uphill shot?
Even if you aim uphill, and your bow is not tilted left or right,
the bubble level will lie to you and force you to tilt your bow.
Try this with a 24-inch level. Hold the level in your hand so that it is still horizontal, but the angle between the level and your arm is 45 degrees, as if you swung a door towards you. Raise your arm towards the ceiling.
The bubble level will not stay in the middle.
Adjust the third axis on your sight is the same as adjust the door swing so that it is 90 degrees.
HOW TO ADJUST 3RD AXIS
3rd axis will affect uphill shots (NFAA field rounds) or downhill shots (from a treestand).
Imagine that your sight ring is a door. If you bump your sight ring into a tree, the sight ring may bend towards you like swinging a door closer to your face. Let's say the sight ring "door" opened towards you 45-degrees. The bubble still reads level when you hold the riser straight up and down.
Now, hang a weighted string from the ceiling.
Kneel down on your knees, load an arrow in a safe spot, come to full draw and anchor.
Line up the weighted string with the left edge of the riser and your limbs.
Take a look at the bubble.
The riser and limbs are vertical because you are lined up with the weighted string.
If the sight ring threaded rod is bent towards you or away from you,
the bubble will not read level even though you are not canting the bow.
Adjusting the 3rd axis of a bow restores the sight ring door swing
back to 90 degrees, perpendicular to the sight frame.
The best way to check is kneeling down on your knees,
aiming up at a weighted string hanging from the ceiling.
If your sight has 3rd axis adjustment, then adjust away.
If you sight does not have 3rd axis adjustment,
you will need to use shims to adjust the entire sight or just the sight ring.