Rich - Actually I agree with what you said, though it would be nice if ABC could be optionally UVW.  It would allow for greater flexibility in machine building within the 6 available axes, because the axes can currently be used for rotary or linear applications.

I haven't followed Mach4 for  some time now so whatever Artsoft will / wants / or decides to do is up to them.
They have option to do whatever and define the basis.

I also don't know the historical sequence of CNC as it has developed over time and just how the standards have evolved  addressing it all.
Different manufactures, proprietary code  / controllers all add to the confusion. But will say that definition of axes from a mathematical point of view have been around a long time.

I will say that my basis of knowledge is whatever is published by Smid on the CNC topic and frankly that is well recognized source.

It is interesting that over time the industrial complexity has evolved and the quest for more is always desired. Haven't seen anything for a 12
axis machine yet.............

BTW, in Mach3, ABC axes can be linear and not rotary  and Mach knows only what you tell it.
So in a sense you can have the equivalent of UVW, but, you can't use those designations for axis definition in the gcode dialect of Mach.

Interesting thread as one learns everyday. Frankly I am becoming "dated"    and I like it!
Simpler life these days my friend,   

RICH

I was never really sure if any standard were published on this, so I googled it and found an Iso publication. ISO 841 - "Industrial automation systems and integration — Numerical control of machines — Coordinate system and motion nomenclature"

Here is some of what it says:

"
Linear motion:
When, in addition to the primary linear motions X, Y and Z, there exists secondary linear motions parallel to the
primary motions, these shall be designated U, V and W respectively. Similarly, for tertiary motions, they shall be
designated P, Q and R respectively. When linear motions exist which are not (or may not be) parallel to X, Y and Z,
they may be designated U, V, W, P, Q, or R as is most convenient.
The primary linear motions should be those nearest the principal spindle, the secondary the next nearest, and the
tertiary are the farthest.
For milling machines, the cutting-bit with respect to a facing slide should be designated U or P if these letters are
available.
For machines with multiple units or many parallel movements, the designation of these motions may be indexed by
using a letter and a number (e.g. X1, X2, ...). The index shall be a positive integer greater than zero. The primary
motion(s) may or may not have an index. Thus it is possible on one machine to have motions with and without
indices.

Rotary motions:
When, in addition to the primary rotary motions, there exists secondary rotary motions, either parallel to A, B, or C
or compounded or gimballed to A, B, or C, they shall be designated D or E (if these letters are available). As with
linear motions, rotary motions may be indexed
"

I have seen screw machines that use X1,X2,X3 etc.... But I can't say I have ever seen a P,Q or R axis.....yet  

I can handle programming my "U" as "A",  I just wanted to keep things the same as all the other machine tools I have operated for the sake of simplicity.  I have a hard time remembering which way is up nowadays 

I know we use U's and W's on our haas lathe so I did a quick look and m4 lathe manual and it has info for that on page 4 but it's not what you are wanting to see but it's there

In Mach 4, UVW controls ABC in a linear fashion.  Simply change A labels to U on the screen and use U in your G code.  (Don't forget to turn on the in/mm display in the DRO.)  Wire and map everything on A.

Steve

Well I'll be damned it worked! 

Thanks Steve.

Glad you are working now! 

I looked at the docs and this was unmentioned in the mill manual.  So I updated the docs.   

Just to be clear for everyone, this is for mill.  For turn, UVW are used for incremental moves of the XYZ axes.  There is no G91 in turn anymore for Mach 4. 

Steve