Siemens SINUMERIK 840DE Programming Manual page 154

Programming Motion Commands
4.15 Thread cutting with constant lead (G33)
Thread chains
By programming several G33 blocks consecutively, you can align several sets of threads in a
sequence. With G64 continuous-path mode, the blocks are interconnected in a look ahead
velocity control so that no speed jumps are produced.
Right-hand/left-hand threads
Right-hand or left-hand threads are set according to the spindle direction:
M3: Clockwise
M4: CCW rotation
4-48
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
Fundamentals