I am curious about Mach´s resolution with simultaneuous movements in X and Z. Maybe the limitation would be related to the steps/per configuration
My engraving machine steps per inch is 253360. Resolution is 1/253360=0.000004" but practicaly speaking it's around 0.000040", but then i had difficulty actualy measuring and confirming that, so i will just just say that you can check a .0001" indication with 10 jog steps.
To bad the spindle with the sharpest point can only scribe a .004 or so line width as that limits the heigth of the engraving.
As far as the lathe goes, when i was doing threading tests,measurements were done on the scribed lines to .0001". The Z lathe axis steps per unit are
20320, thus resolution is under a tenth, so lets just say 0.0001". That can be confirmed easily over different increments / total length or whatever.
Now the X axis is 12700, thus it's resolution is like half the Z , but that X axis screw is a high grade ball screw and can match the Z any day of the week.
But practicaly speaking, all of the above means nothing, if at the end of the machining, the shaft is bigger than the hole and won't go in....
RICH