M_thread

Remix of https://www.thingiverse.com/thing:3712000 Removed global variables, making the modules more stand-alone. This way, you can include the file in to your own scripts, and call multiple instances of threads. Requires helical_extrude(), which is included, just make sure that it is in the same folder. The M is for M profile. This is technical name given to the 60deg V-form thread that is most commonly used. subtrahend: the portion(s) that is removed from the solid, when you use difference(). eThreadM is for external thread iThreadM is an interal thread cylinder iThreadSubM is an internal thread option that is meant to be the material removed.