Program A axis to rotate as a Spindle

[crj1203ar]

just added a 4 axis (" A axis" via a stepper motor to my system).  
I want to turn it on so that it continues to rotate at a constant speed while Mach3 runs my program (g-code) instead of having to
Program each line with the "A *********.*********" code" to have the A axis spindle.  
So how do I program the 4th axis to turn on at the beginning of my g-code file, then turn off at the end?

Any suggestions?  Thanks.

[BR549]

It is not possible using MACH in the NORMAL manner.

HOWEVER  IF you had a "manual spindle control " ( you turn it on/off by hand) you could set up the A axis to be run AS a spindle with step direction control. Speeds would be limited though.

Just a thought, (;-) TP