Siemens SINUMERIK 840D sl Operating Manual page 120

Working in manual mode
3.7 Thread synchronizing
See also
Thread turning (CYCLE99) (Page 336)
120
Press the "Teach-in counterspindle" softkey if you are working at the
counterspindle.
Note:
The thread synchronization is activated by teaching in a spindle. In this
case, the synchronizing positions of axes X and Z and the
synchronizing angle of spindle (Sn) are saved in the Machine and
displayed in the screen form.
The selection boxes for main spindle and counterspindle indicate
whether thread synchronization is active for the particular spindle (yes =
active / no = not active).
5. Now carry out the "thread turning" machining step.
6. For the main spindle or counterspindle, select the "no" entry to
deactivate thread synchronization.
Operating Manual, 02/2012, 6FC5398-8CP40-3BA0
Turning