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.

TFOX,

Here is the method that came with my G5 Optix ME.
1. Using a plumb bob, or similar, hang from elevated position. i.e. ceiling
2. Nock an arrow and kneel down on the floor while holding bow.
3. Draw bow back with nocked arrow and aim up toward the plumb bob. now align the top and bottom pin to the plumb bob. Take a look at the bubble vial.
4. Let bow down from full draw carefully. Make adjustment to bubble vial by loosing and tightening set screws.
5. Repeat steps 3 & 4 until bubble vial is perfectly aligned at full draw.

What's your thoughts on this method?

That may get you close because you are actually drawing up on an angle and shooter induced torque will be compensated for but what is going to happen if your riser isn't square with your arrow?


Your sight bar is at an angle,therefore,you have not set the bubble square with the arrow.Meaning your bubble will be off on downhill/uphill shots.


It may be close or it may not.


The best way to check isif the sight can bemoved in and out.Take the sight and move it in as far as it will go.Shoot a couple arrows at say 30 yards.Then move the sight bar out as far as it will go then shoot again.The arrows will impact on a differenthorizontal plane but they should hit on the same vertical plane.(same left and right).


If they are not the same,shim the bar in or out so that they are the same plane.Then your 3rd axis will be set properly,via the 4rth axis.


Can you see why this subject has so many confused,even the manufactuers of the sights?

I see what you are saying. Before I bought my sight I was reading about 3rd and 4th axis and just thinking to myself this is confusing. I thought about buying a sight with 4th axis and just figured the heck with it.

Ijust started using the bubble after owning the bow for 8 months.

Will moving it as little as3/4 inch have enoughaffect for testing? I only have 2 holes and no sliding bar on the G5.

If the bow is strictly hunting then that should be more than enough to set up the 3rd axis.


Funny you need to use the 4rth axis to set the 3rd axis properly.The 4rth really has no real advantage when set.Unless you are using a slide bar andslide it in to gain yardage for long range shots.



Here is a diagram explaining the different axis.

It's strickly a hunting bow. So, unless I'm shooting long range (50 yds or more?) I shouldn't really worry about the 4th axis anyway?

Don't worry about the 4rth,unless the 3rd is off.regardless if it is a hunting bow or target bow.


3rd has to be square with the arrow to be accurate.Most people use the bar to set the 3rd axis,not the arrow.


Go to the link I posted and read up on how they tell you to set the level,then it should come together in your mind.


4rth just aligns the arrow with the bar,making setting the 3rd to the bar accurate.

"T" man I remember when the 4th axis conceptwas put up over on "THAT" other forum and it caused a big stirr because people did not understand it.

I guess I am lucky enough to live close to Ken Stanislawski when him and Gene developed the Tek-tech 4th axis to see it first hand and the benefits of the concept.

The 3rd axis sight leveler is what I use to set my 3rd axis in conjuction with the 4th axis of course

Ausie,is it Gene that would post pictures of his sight setup with bow cant?


I wanted to post a picture of that in another discussion and didn't have any idea of where to find it but I was pretty sure he had something to do with the 4rth axis device.

I was doing this before that tool ever came out,I learned it from someone that has setup bows for a couple world record holders.

That is a sweet setup too,if I still shot a slide bar,I would be using that instead of the old creditcards that I used for shims.Of course I probably would have made my own,I am cheap that way.



See level above,I wouldn't even buy one of those,I made mine but mine is much better.[:-]

If you change the left/right of your arrow say for paper tuning, would you not need to redue your fourth axis adjustment? In your illustrations is the bubble not in the center because the level is twisted as you are laying it down, or putting it in the next plane? If this is the case then will it not be fine on your bow as long as you set the 3rd axis to your style of grip so that it is perfectly perpendicular to you. Then when you are in the other planes, uphill/downhill, it will be fine? Right? Im a little bit confused.