I have converted my lathe and have run some wizards with a minimum of problems and now want to try writing some Gcode.  I have the Smid book and using it tried to write a little program for facing using a G94 code.  I only ran it on the computer, but nothing would make it work.  Then I entered Smid's example right from the book for straight turning which uses a G90 code - again it traced a goofy path not making interative cuts.  When I looked at some of the wizards that came with Mach3 none of them seem to use these higher G codes.  So what G codes can be used in Mach3?  Do different programs use different G codes? 

Thanks.

Refer to the Turn manual to see which canned cycles are supported but afraid you will not find many in Turn.

Hood

Well that is ugly.  I was trying to stay away from CAD, but if I do start from CAD for the lathe do I do half drawings, that is from the centre line of the peice to the edge, given that the peices are always symetrical.

There are different "dialects" of gcode. Some are manufacturer specific  ie;Fanuc / Hoss etc and that is true of canned cycles.
So as Hood replied, consult the Mach3 Manual. Mach4 when done should be more closely aligned with Smid.
In a similar way, many CAD/CAM do things differently, and they usualy provide specific post processors for popular controllers like Mach.

 As far as CAD goes, it all depends on the CAM software for what is acceptable when you don't use their drawing software.

So the example you mention from Smid book ie; G90 canned cycle is actualy a command for ABsolute Distance Mode in Mach.

All of the above is called "having fun in learning curve"...

No harm in seeing how gcode is provided from NFS Turn Wizard, LazyTurn, and other Lathe specific software.
There are even programs that produce Gcode directly while in CAD ie; Autocad.

FWIW,
RICH