MBG 1st/2nd Axis Adjustment Misnomer

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Oct 16, 2014
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TLDR: MBG 1st Axis adjustment is just a misnamed 2nd axis adjustment, and the 2nd axis adjustment just sets the level - not the sight.

I see a LOT of confusion on here about axis adjustments, and a lot of the information on the vendor sites make it a lot worse! Engineer here - overthinking beyond my shooting ability - something that drove me crazy when learning how to set up my new bow. Thought I'd share to dispel companies claiming 1st axis adjustments when they are just adjusting the 2nd axis and then setting the built in level and calling it a second axis adjustment, and help clarify anyone else that is confused!

According to every source I can find the 1st axis is a line left to right, the second axis is a line straight through the center of the sight, and the third axis is vertical. (http://www.lancasterarchery.com/blog/the-three-axes-of-a-bow-sight/)

So - the level must be perpendicular to the axis and horizontal in our case of setting 1st and 2nd axis. To set the first axis the level would be facing front and back, and the second axis the level would be right to left. On the MBG Ascent series (I have the assault) the step to adjust what they call the "first axis" is to hold a level against the site tape post and rotate clockwise facing the front of the site - which is around the 2nd axis! The micro adjust on the assault pushes a little pin inside right or left on the bottom. If this was an actual 1st axis adjustment the screws at the top and bottom of the football would adjust the top and bottom IN AND OUT not left to right.

Then what they consider the actual 2nd axis adjustment is just setting the sight ring to match the rest of the sight that you already setup. It's not actually rotating your housing to be level with your bow, just matching the ring level with your 2nd axis leveled sight (which you got from the "1st axis" adjustment). I have absolutely no idea why this would be adjustable and not factory leveled to the pins.

Any easy way to think about the fact that you are not adjusting two different axis with these two different adjustments (the football and the sight ring) is that:
1. The level is in the same orientation for both adjustments
2. Both adjustments rotate the sight in the same direction.

Here are two examples (as well as what MBG considers "1st axis") that make no sense.

 
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RosinBag

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I am no engineer, but i think you are overthinking it. The video is explaining it correctly. Although i personally think the 3rd axis needs to be done at full draw.

1st axis, when sights have them, set the sight extension or the bar to be level with the riser / string.

2nd axis, will set the level in your sight to be level with the 1st axis / bow riser / string.

3rd axis, sets the level to be level with all the above when the bow is in an angled position, either up / down.

Many sights don't offer a first axis adjustment so you have to hope the sight mount and riser mount are machined very well to mate to one another or you could shim it if needed.

Keep it simple.
 
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Gumbo

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I have noticed this too...but the way MBG has their three adjustments set up works so it doesn't bug me too much. And I like that you can adjust the bubble instead of relying on the factory to get it right. I had a SH Hunter bubble that was off and it drove me nuts. Besides, most people have no clue what the axes are and how/why they work anyway, they might as well call them Larry, Moe, and Curly.
 
OP
S
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Oct 16, 2014
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Look at a single pin sight, 1st axis adjustments would do absolutely nothing. The only first axis movement that is made is when you're pointing your bow down or up, or sliding your sight up and down(which rotates the bow forward, not sideways). You never shoot a bow with your first axis level. Every one of the different distance pins or slider settings makes you line up the target by rotating your bow on the first axis to adjust for yardage.

1st axis, when sights have them, set the sight extension or the bar to be level with the riser / string.

This is highlighting my point about the 1st axis - if you're leveling anything to the riser you're leveling it to the second axis (rotating right or left). It may be the FIRST in sequential order of axis adjustments you make when setting up a bow, but it is not a "1st axis" adjustment.

2nd axis, will set the level in your sight to be level with the 1st axis / bow riser / string.

Again, if you're leveling anything to the bow riser/string you're just leveling another component to the second axis.

And I like that you can adjust the bubble instead of relying on the factory to get it right.

This totally makes sense to me, but still seems like a quality control issue!
 

RosinBag

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That is exactly why you are overthinking it and will confuse people. You are interpreting the first axis to the engineer or science aspect verse what the archery industry refers to the axis’s. You are essentially redefining what most people know it as to fit an engineers thinking.

It probably would be better to call it Larry, Moe and Curly and then there would be no interpretation.

And every competitive target archer will level their sight to the string/riser. There were a few that level it to their natural can’t of the bow, but I don’t know if any left as it is not as repeatable.

But ultimately you can set your sight up anyone you want or call the adjustments anything you want.

The attached video is correct in their terminology for the industry and that may not match what an engineer would refer to it as.
 
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