Thank you Michael for showing me how to find input names of undocumented commands. I'm still having difficulties with the sweep but need to address this with fresh eyes.

In the meantime here's a working script that produces a 30 mm long piece of metric M10 x 1.5 rod. The thread profile is simplified without radius.
By editing the variables at the beginning of the script file different threads can be made.
The longer the thread length though the longer it takes for the sweep and boolean operations to finish. Making a 300 mm long rod took between 5 and 10 minutes (I didn't stop the exact time).

Maybe a good script to measure performance. There's the moi.ui.showViewportDisplayTime=true; function to measure vieport update time but is there some sort of time function in the MoI JavaScript language?