There seems to be some misleading reasons we need 3rd axis adjustment.Some think the only reason for it is to compensate for shooters torque(that is part of the reason)


Also,there seems to be some bad info on how to properly set a 3rd axis.You do not set it to your sight bar,however that is the easiest way to get it set,1 more step must be taken if you choose to use the bar.You must set the sight bar square with the arrow.



Here are some pics to help explain why this is true.


This picture is of a level sitting on a level surface.




Here is a pic of the same level being rotated as if you are shooting downhill.You can see the level is starting to move out of center.reason is you are changing planes and the level isn't level with the next plane.







Here is the same level laying almost completely flat on the next plane.See how the bubble is almost gone.







This is exactly what will happen if a level isn't set properly in the 3rd axis.




Here is a level that I made that is level and square in all planes.See how accurate it is as you rotate as if shooting downhill.


Flat on level surface.





here it is as if rotated slightly downhill.
Notice,it is still level.





Here it is laying flat on the surface and still level.





Here is how most check there 3rd axis.To the bar.





The problem is that as proof from the above pics,if the level isn't square in all planes,the level will have to be adjusted out of level to read level.Remember the arrow represents another plane,therefore,it also has to be square with the level.


If the level is set on a table to the sight bar,as you can see,if the arrow isn't running EXACTLY parrallel with the sight bar,it will not be accurate.



So there are a couple of solutions to this problem.You can continue to use the sight bar to set the 3rd axis and then make sure the sight bar is running parrallel with the bar.All that is needed to do this is just shim the sight bar so that when it is adjusted in and out,the arrow will have the same left and right impact.That will square the arrow to the bar and your 3rd axis will be dead on.

This will also take care of shooter induced torque that many think is the reason for 3rd axis adjustment.


Or you can buy a product like the one in this link that makes the adjustment easier.
http://www.archerytech.com/


The other way is to set up the 3rd axis actually shooting on a hill and that require much trial and error imo.That will automatically get the arrow square with the level and sight.


Hope this makes sense and is usefull info to someone out there.




This info is mainly for the serious competitive shooter that needs the extra advantage of properly set up equipment.

Hunting bows will see little benefit to this because you can miss the spot by an inch or two and still have a dead animal.