Siemens SINUMERIK 840DE Programming Manual page 159

The parameter for the lead is based on the taper angle (calculated from the longitudinal axis
lead angle <45° to the outside of the taper lead angle >45°).
Start point offset SF - production of multi-turn threads
Threads with offset cuts are programmed by specifying starting point offsets in the G33
block.
The start point offset is specified as an absolute angle position at address SF=. The
associated setting data is changed accordingly.
Example: SF=45
Meaning: Start offset 45°
Value range: 0.0000 to 359.999 degrees
Fundamentals
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
Programming Motion Commands
4.15 Thread cutting with constant lead (G33)
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