# X-Y-Z Confusion



## Logan Novice (May 5, 2021)

I've never understood why some machinists are so uncomfortable with eliminating the "Z" axis reference when applying two dimensional DRO scales to their lathes. In common practice, the Cartesian coordinate system specifies the "Y" axis as a two dimensional vertical coordinate. But rotating the scale to a horizontal plane places the Y axis on a platform which moves toward/away from the observer and the X axis moving left and right. Even with my mill, the X-Y axes are horizontal with the Z axis reserved to vertical. What am I missing?


----------



## jwmelvin (May 5, 2021)

Z-axis is oriented with the spindle. That’s the convention, as I understand it.


----------



## Ken226 (May 5, 2021)

Yup. Z is the axis on which the spindle rotates.   It's still drives me nuts that my DRO says X and Y.    It's what I get for going cheap.

Jump onto a cnc horizontal mill for some MDI work, right after working on a vertical machine


----------



## benmychree (May 5, 2021)

Back in the dim olden days, it was table feed, saddle feed, and knee up/down, and spindle feed, if so equipped, with a HBM substitute head up/down for knee up/down.  I never heard alphabet terms until the coming on NC.  Just imagine, we made parts without NC or DROs!


----------



## Logan Novice (May 5, 2021)

Ken226 said:


> Yup. Z is the axis on which the spindle rotates.   It's still drives me nuts that my DRO says X and Y.    It's what I get for going cheap.
> 
> Jump onto a cnc horizontal mill for some MDI work, right after working on a vertical machine


Thanks or the diagram, Ken.  It helps make my point.  If "axis" is the imaginary line about which a body rotates, and "Z" is the axis on which the spindle rotates, then (assuming that the spindle in this image is vertical) the "Y" in the diagram should be labeled "Z".  The "Y" designation might apply to a graph's vertical line, but it don't work for me on a machine. And, OMG, this one tosses in a "W" and "V".


----------



## Ken226 (May 5, 2021)

Logan Novice said:


> Thanks or the diagram, Ken.  It helps make my point.  If "axis" is the imaginary line about which a body rotates, and "Z" is the axis on which the spindle rotates, then (assuming that the spindle in this image is vertical) the "Y" in the diagram should be labeled "Z".  The "Y" designation might apply to a graph's vertical line, but it don't work for me on a machine. And, OMG, this one tosses in a "W" and "V".



That diagram is of a horizontal mill.

The spindle is the little horizontal pee-pee looking doohickey sticking out where the W is.  Consider the pee-pee to be a 1/4" end mill.

I believe the "w" axis reference indicates that it has a horizontal quill feed.

I have no idea what the "V" is supposed to be..

In that diagram, the Z -  feeds in, towards the spindle or Z+ feeds out, away from the spindle,  same as a lathe or vertical mill.

Y is up/down movement of the knee, or head if so-equipped.   X is left/right, same as a vertical mill.

Basically, same as a vertical mill except with the z / y plane rotated 90° around the x axis as seen from the X+ end of the table.


Funky looking contraption isn't it?


----------



## Winegrower (May 5, 2021)

For my little horizontal mill, the table left and right is X, forward/back is Y and the vertical lift is Z.   Anything else, hey, this is just a hobby.


----------



## Mitch Alsup (May 5, 2021)

Question::

If you have a horizontal mill and add the vertical mill head, does that change the name of the travel directions?

So:: horizontal mill:: up/down = Y :: in-out = Z :: left-right = X
in Vertical config::::  up/down = Z :: in-out = X :: left-right = Y

Does anyone change their DRO readouts to correspond ?


----------



## Logan Novice (May 5, 2021)

Ken226 said:


>



Who makes that beauty?


----------



## Ken226 (May 5, 2021)

Mitch Alsup said:


> Question::
> 
> If you have a horizontal mill and add the vertical mill head, does that change the name of the travel directions?
> 
> ...



On manual equipment it doesn't make any difference.  You could call them ed, bob and Steve, and get the same results.



It's just that in certain industries, people get into the habit of following certain rules, and carry it over to their personal hobby stuff too.    Like when your wife tells you the helicopter light came on in the car.  If your a car guy, your first thought Is "huh!?"  but there are likely plenty of husband's out there who'd totally understand the reference.   And if you both know what she's talking about, does it really matter which word she picks to describe it. 

The helicopter light:




Like "drill bits",  or the "motor" in a car and and a ton of other terms that are normal to most. It only bugs a small subset of people who work in those specific industries, and have either formal education or have ingrained habits regarding terminology rules.

  GD&T terminology gets alot of machinists and Engineers rolling their eyes,  probably the same way infantry soldiers would roll their eyes when the engineer describes how to put a clip in his gun and cock it.



On CNC equipment, you wouldn't want a program with 100,000 plus lines of software generated code sending x, y and z commands to the wrong servo motors.

If a guy is using a cnc vertical mill, and swaps to a horizontal spindle,  he would need to set his cam software up to generate the correct commands to the correct servo drivers, and that would likely also involve change the designations in his cnc motion control software.  I only have a vertical spindle on my cnc mill,  but I could reassign the axis designations in about 30 seconds if needed.

As to manual equipment. I just refer to each axis as my training and experience justify.  It helps me avoid mistakes. 

But, if someone asks, I like to answer with correct textbook answers. It's not meant to imply that anyone should change the way they do things.


----------



## sdelivery (May 5, 2021)

lol, I came out of a CNC Boring mill shop. 
W axis is the saddle the table runs on, the table being X
The headstock rides vertically and the quill is the Z axis.


----------



## sdelivery (May 5, 2021)

Then there was the Wasino 7 axis lathe with live tooling.
The only lathe I have ever seen with a Y axis.


----------



## brino (May 5, 2021)

The text from my wife said the "yellow submarine" light was on....



-brino


----------



## Ken226 (May 5, 2021)

So, like this Cadem cnc boring mill, from Cadems website?





A description of the rules, below pic in the link.   Cadem is a manufacturer of CNC equipment.









						CNC axes directions on Horizontal Machining centers (HMCs) - Cadem
					

CNC axes directions always follow a convention, and all CNC machine manufacturers follow this convention. Here's the xplanation for HMCs..




					cadem.com


----------



## darkzero (May 5, 2021)

Ken226 said:


> Like when your wife tells you the helicopter light came on in the car.  If your a car guy, your first thought Is "huh!?"  but there are likely plenty of husband's out there who'd totally understand the reference.   And if you both know what she's talking about, does it really matter which word she picks to describe it.
> 
> The helicopter light:





brino said:


> The text from my wife said the "yellow submarine" light was on....
> View attachment 365001
> 
> 
> -brino



Haha, never heard it called the helicopter light before, that's a good one!

Reminds of the guy pooping indicator.


----------



## davidpbest (May 6, 2021)

brino said:


> The text from my wife said the "yellow submarine" light was on....
> View attachment 365001
> 
> 
> -brino


Still ROFLMAO.


----------



## Logan Novice (May 6, 2021)

Yeah, Ken, that "helicopter" light is a standard unique to itself.  But ...  the reset procedures are anything but standard.  I guess it's important to have a proprietary helicopter light reset system. Go figure.
As for the X-Y labels.  I'll just stick with carriage X and cross feed Y so I don't crash the machine.  Now all I have to do is remember the directions for the feed levers.


----------



## hman (May 6, 2021)

ROTFLMAO!!!!!

PS - regarding the "helicopter" light ... it looks more like an autogyro to me.


----------



## ARC-170 (May 6, 2021)

Here's what I was taught and what I taught my Engineering students:

Use the "Right Hand Rule": put your thumb and forefinger on your right hand out like you are making a gun. They will be at right angles to each other in the same plane as your palm. Stick your middle finger out at right angles to your palm ("normal" to your palm, if you prefer that term; it's the same). Your thumb is the X-axis, your pointer finger is the Y-axis and your middle finger is the Z-axis, all pointing in the positive direction. The Z axis is the axis of rotation on any machine.
So a lathe technically doesn't have an X-axis, just Y and Z.
We tend to refer to the left and right direction as the X-axis, and forward and back as the Y and up and down as the Z. Using the RHR gives us a common language and reference for any machine.


----------



## Ken226 (May 6, 2021)

ARC-170 said:


> Here's what I was taught and what I taught my Engineering students:
> 
> Use the "Right Hand Rule": put your thumb and forefinger on your right hand out like you are making a gun. They will be at right angles to each other in the same plane as your palm. Stick your middle finger out at right angles to your palm ("normal" to your palm, if you prefer that term; it's the same). Your thumb is the X-axis, your pointer finger is the Y-axis and your middle finger is the Z-axis, all pointing in the positive direction. The Z axis is the axis of rotation on any machine.
> So a lathe technically doesn't have an X-axis, just Y and Z.
> We tend to refer to the left and right direction as the X-axis, and forward and back as the Y and up and down as the Z. Using the RHR gives us a common language and reference for any machine.



I bet it won't surprise you at all to hear,  that's exactly what I was taught.  When I was an engineering student. .


----------



## Logan Novice (May 8, 2021)

The right hand rule must be the most popular teaching tool in existance.  I learned it in my early exposure to electronics to explain faradays law of electromagnetic induction.  I'm gonna add it to my newly discovered helicopter light.  I'm gonna pass on the guy pooping indicator.  It doesn't get that cold here.    Luvin it .....


----------



## sdelivery (May 8, 2021)

I personally like yellow submarine best!
I think that might be the Beatles influence on me...lol


----------

