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3rd Axis? "Why don't you explain this to me like I'm five" -Michael Scott

Andre Bell

Andre Bell

New Member
Joined
Jun 30, 2022
Messages
27
Okay, so I was at the archery store looking at things I don't really need but I came across a Trophy Ridge sight that has 3rd axis adjustment. I tried looking it up but I'm still lost. Can anyone simplify what exactly 3rd axis is, how it's used, and if it's even necessary to have? Thank you!
 
The 3rd axis pertains to the yaw alignment of your sight to your bow. The steeper angled shots you take the further left or right your bubble level will be off, hence canting the bow and throwing off your shot.

For the majority of treestand/saddle hunting situations it's a moot point since at those typical distances the amount of error is almost negligible. This becomes a particular issue when hunting out west in steeper terrain at longer shots.

EDIT: I also wanted to note that a 3rd axis adjustment should be calibrated when your bow is at full draw. Your riser will flex under the stress at full draw, so what may look to be an accurate 3rd axis adjustment at rest could be off at full draw.
 
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heretic said:
The 3rd axis pertains to the yaw alignment of your sight to your bow. The steeper angled shots you take the further left or right your bubble level will be off, hence canting the bow and throwing off your shot.

For the majority of treestand/saddle hunting situations it's a moot point since at those typical distances the amount of error is almost negligible. This becomes a particular issue when hunting out west in steeper terrain at longer shots.

EDIT: I also wanted to note that a 3rd axis adjustment should be calibrated when your bow is at full draw. Your riser will flex under the stress at full draw, so what may look to be an accurate 3rd axis adjustment at rest could be off at full draw.
Click to expand...
Thank you for the explanation since I didn't understand how it may or may not of applied to saddle hunting but more so out west for elk. It also sounds like it's a two person adjustment so I'll keep that in mind if I ever decide to go that route.
 
It can be a one person adjustment. If you've got the equipment a hooter shooter will do, if you're cheap like me a plumb bob will suffice. I'm sure there's youtube videos out there that show you how to do it.

Alternatively you can always try your local bow shop! The one I went to wouldn't even consider a 3rd axis adjustment unless you could explain what it does.
 
If your "third axis" is crooked, when you point up or down your level isn't level.

I wouldn't overlook it completely for stand hunting. How much it matters depends on
  1. How much arrow drop (heavy arrow guys are more vulnerable!)
  2. The angle you're shooting at.

So if you're shooting a heavy arrow from a hilltop it comes into play sooner.
 
heretic said:
It can be a one person adjustment. If you've got the equipment a hooter shooter will do, if you're cheap like me a plumb bob will suffice. I'm sure there's youtube videos out there that show you how to do it.

Alternatively you can always try your local bow shop! The one I went to wouldn't even consider a 3rd axis adjustment unless you could explain what it does.
Click to expand...
Heck even just take some shots at the highest angles you expect to see and see where they group.
 
It's used to boast about how much you know about archery and how awesome you are. Honestly that's about it imo. But it's if your sight house is square to the horizontal plane or not. It can come into play at long (very long) ranges and steep angles but for 99% of hunters just make sure the axis is square when you set it up and don't fog your brain with too much unecessary physics.
 
Andre Bell said:
Okay, so I was at the archery store looking at things I don't really need but I came across a Trophy Ridge sight that has 3rd axis adjustment. I tried looking it up but I'm still lost. Can anyone simplify what exactly 3rd axis is, how it's used, and if it's even necessary to have? Thank you!
Click to expand...

For short range shots, it isn't needed, especially if you have a quality sight and all the holes are tapped accurately.

Holding your bow, think of the sight like a door, opening that door is a rotation around the 3rd axis, in a sense.

You want the door shut, so to speak, which means, in a sense, your line of sight is at a perpendicular to it and it is perpendicular to the bow....if the sight is "off" this is akin to this door being slight ajar (in either direction).

Now imagine, instead of a door, you are holding a bubble level where the sight is.

If everything is square, then if you were to mimic a downward shot (by rotating the bubble level downward like the sight would be on a downward shot)....then the little bubble will stay centered no matter how you point downward. Now, instead, imagine the bubble level is not square....but open like a door a bit. If you rotate downward, now the bubble will go to the high point of the level's bubble chamber (to the right the way I'm envisioning it). Now, if you try to rotate the bow to put the bubble in the middle, you'd have to rotate the bow clockwise (around the second axis) and throw everything off.
 
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Really good way of describing it @raisins . I had a hell of a time grasping it until I saw a visual depiction of it on Rokslide I believe.

I would be interested in seeing some theoretical calculations. Not doing them I hate math lol. There has to be a way to work out a formula like at X degrees 3rd axis adjustment and Y distance and Z angle what is the result.
 
elk yinzer said:
Really good way of describing it @raisins . I had a hell of a time grasping it until I saw a visual depiction of it on Rokslide I believe.

I would be interested in seeing some theoretical calculations. Not doing them I hate math lol. There has to be a way to work out a formula like at X degrees 3rd axis adjustment and Y distance and Z angle what is the result.
Click to expand...

Thanks, except I got counterclockwise wrong and just edited it :)
 
raisins said:
Now, instead, imagine the bubble level is not square....but open like a door a bit. If you rotate downward, now the bubble will go to the high point of the level's bubble chamber (to the right the way I'm envisioning it). Now, if you try to rotate the bow to put the bubble in the middle, you'd have to rotate the bow counterclockwise and throw everything off.
Click to expand...
If your sights off by say 1 degree and taking a 20 yard shot from 30 ft up, my preliminary and possibly wrong "envelope Math" gives a 6 in miss. That seems field relevant (and a general reminder to watch your bubble and not torque, because small changes make big differences).

(I think I may have been semi-burned by a similar error and this thread is a great reminder that I need to check my leveling and get some elevated practice in. Still had clean recoveries, but in a "better lucky than good" way. Blamed a form error but both shots were from a high position shooting downhill and missed by a consistent amount.)

This is one of the many reasons elevated practice is useful. Regardless of the "why" if you're off you'll know it.
 
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elk yinzer said:
Really good way of describing it @raisins . I had a hell of a time grasping it until I saw a visual depiction of it on Rokslide I believe.

I would be interested in seeing some theoretical calculations. Not doing them I hate math lol. There has to be a way to work out a formula like at X degrees 3rd axis adjustment and Y distance and Z angle what is the result.
Click to expand...
Punch your numbers in here. This assumes that you adjust your aim so that the (wrong) 3rd axis is level as you change aiming angle.

docs.google.com

3rd Axis Error Estimate

Sheet1 Fill in the green, and it calculates the orange. If your third axis is off, you aim the bow left/right as you shoot upward or downward. The maximum error is if you shoot vertically (off by the full 3rd axis error). There's no error when you shoot horizontally. How Far from the target (g...
docs.google.com docs.google.com
 
mattsteg said:
If your sights off by say 1 degree and taking a 20 yard shot from 30 ft up, my preliminary and possibly wrong "envelope Math" gives a 6 in miss. That seems field relevant (and a general reminder to watch your bubble and not torque, because small changes make big differences).

(I think I may have been semi-burned by a similar error and this thread is a great reminder that I need to check my leveling and get some elevated practice in. Still had clean recoveries, but in a "better lucky than good" way. Blamed a form error but both shots were from a high position shooting downhill and missed by a consistent amount.)

This is one of the many reasons elevated practice is useful. Regardless of the "why" if you're off you'll know it.
Click to expand...

I haven't ran any detailed math on it, but my anecdote is that a few degrees along the 2nd axis doesn't move it that much when shooting flat at 20 yards (despite =tan(radians(1))*20*3*12 being 12.6 inches....which is a quick back of the envelope from me to represent that...in Excel talk). I think it might be because it moves your sight over to the right (let's say) and then you have to move the whole bow left to get the sight back on target (compensating effect and why gangstas can kinda hit with their gats held sideways).
 
mattsteg said:
Punch your numbers in here. This assumes that you adjust your aim so that the (wrong) 3rd axis is level as you change aiming angle.

docs.google.com

3rd Axis Error Estimate

Sheet1 Fill in the green, and it calculates the orange. If your third axis is off, you aim the bow left/right as you shoot upward or downward. The maximum error is if you shoot vertically (off by the full 3rd axis error). There's no error when you shoot horizontally. How Far from the target (g...
docs.google.com docs.google.com
Click to expand...

I'll check it out, thanks.
 
raisins said:
For short range shots, it isn't needed, especially if you have a quality sight and all the holes are tapped accurately.

Holding your bow, think of the sight like a door, opening that door is a rotation around the 3rd axis, in a sense.

You want the door shut, so to speak, which means, in a sense, your line of sight is at a perpendicular to it and it is perpendicular to the bow....if the sight is "off" this is akin to this door being slight ajar (in either direction).

Now imagine, instead of a door, you are holding a bubble level where the sight is.

If everything is square, then if you were to mimic a downward shot (by rotating the bubble level downward like the sight would be on a downward shot)....then the little bubble will stay centered no matter how you point downward. Now, instead, imagine the bubble level is not square....but open like a door a bit. If you rotate downward, now the bubble will go to the high point of the level's bubble chamber (to the right the way I'm envisioning it). Now, if you try to rotate the bow to put the bubble in the middle, you'd have to rotate the bow clockwise (around the second axis) and throw everything off.
Click to expand...
THANK YOU!!!!!
 
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