Hi-
Just a general question on threading.    I know Mach 3 starts the spindle when it receives a pulse from the spindle sensor and that assures that the pass always starts in the same rotational position of the part.  As the cut progresses, does Mach 3 adjust spindle rpm to maintain the proper ratio to carriage travel, or does it adjust the carriage feed rate to match the spindle rpm? 

Thanks MM

Mach varies the Z axis feed to synch with the spindle.