Auto 3D Knob design
Found this knob building script: https://www.thingiverse.com/thing:54024
Its for OpenSCAD, a simple cross platform cad program.
Super easy, just open and edit the script in openscad, saving auto updates the 3d image.
Then export as an svg and do your thing in Blender!
Also, just searching for knobs on thingiverse is a good resource.
Here's an example of using the script... have phun evryone :)