How does the double threading work?
It uses 6 clockwise multi-start threads which means that you machine a thread starting from 0 degrees then index the machine by 45 degrees and machine the exact same thread again. Repeat that 6 times.
We then machine the exact same thing again but this time anti-clockwise.
Then 1x clockwise nut is machined with the same multi-start thread pattern and 1x anti-clockwise version.
Then the magic happens.