Siemens SINUMERIK 808D Programming And Operating Manual page 35

Double-start thread:
Format
With the commands "G32 X (U)... Z (W)... F... Q... ;", the spindle rotates by the angle specified with the address character Q
after the output of the start-point pulse. Thereafter, the thread cutting starts in the direction of the end points specified with X
(U) and Z (W) with the lead specified with F.
Specification of the address Q while cutting multiple-start threads:
Smallest input increment: 0.001°
Programmed range: 0 ≦ B < 360.000
Calculation of the start angle in case of multiple-start threads
In general, the start point for the thread cutting is defined with the setting data $SD_THREAD_START_ANGLE. In case of
multiple-start threads, the angular offset is calculated between the individual start points by dividing 360° by the number of
threads. Examples for multiple-start threads (two-, three- and four-starts) can be seen in the following figure.
Calculation of the start angle in case of multiple-start threads:
Programming and Operating Manual (ISO Turning/Milling)
35
01/2017