You can use/call a SUB from a remote dir. It does NOT have to be in the Gcode program file (;-). You can also add in the #vars at the same time as the call. Just place the sub in the SUB directory

M98"Tapfile.nc" #1=********* #2=********* #3=*********

Just a thought, (;-) TP

THe G84 works very well as is.  I use it with the G95 to make thread feedrates very easy. NOW you do have to use a floating tapp holder.

m3 s100 m8
G95
G84 Z-.5 R.1 F[1/20]         ( Done this way all you do is place the TPI in where the 20 is)
G80
G94         

Great, I was wondering if a sub could be called remotely so that is the best solution.

The G84 when ran here appears to work fairly decent but since there is no dwell after the spindle reverse, the feed starts out of the hole while the spindle is still spinning up to RPM.  It's only a 0.5 second dwell I use, but when it's not used, the floating tap holder is extended a good ways by the time the tap clears the hole and causes a pretty bad snap back.

Thinking about it, I'm sure the Pitch could be modified some in the G84 parameters to reduce this.

Richard