There are alot of ways to create Threaded Nuts n' Bolts in FreeCAD, but this way has to be the simplest.
Real Thunder FreeCAD: https://github.com/realthunder/FreeCA...
Timeline:
0:00 - Introduction
0:16 - Bolt Construction
2:50 - Nut Construction
4:42 - Prototyping (3D Print)