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Difference between all the X,Y and Z axes? Answered


I am new here and only registered to get access to a CNC build which I really like. Now m questions is, as I look at so many of the builds, what defines the axis? Some use Z to go up and down, others mentioned it being the Y-axis, even saw a few saying X.

Is it up to the builder or up to the software?

Kind regards,


I'm using grbl for my CNC as the G-code parser/ motion controller. Typically the Z- axis is where the milling/drill/laser/pen tool is attached and it typically moves in the vertical/up-down direction. I recommend using grbl it provides a lot of flexibility & is free.

Things can get a little confusing when it comes to CNC and axis as it goes against what I was always taught in math. I've tried to explain the commonly used CNC axis labels below:

Z = vertical axis

X and Y = 2-axis on the horizontal plane

I've attached some images to better illustrate.


DId you make those two drawings yourself? Both of them are "wrong", in the sense that you've defined left handed coordinate systems in both cases. Assuming you follow the universal convention that (0,0,0) is at the vertex of the arrows, and the arrows point in the positive direction along each axis.

It's also a bit unfortunate that your two drawings chose opposite colors for the x and y axes.

Ultimately the axis can be defined as whatever you want, depending on the parameters in the software/code. But the examples I've provided are the most common usage.

Thank you very much for the short but clear answer. I will have to keep this in mind when building my CNC.