Complete tutorial to make a herringbone gear in autocad
Here is complete video showing each step to model 3d herringbone gear with autocad,
you can find lots more similar tutorials here
Answered with a tutorial: https://grabcad.com/tutorials/how-to-make-herringbone-gear-in-autocad
1st draw a circle 2nd plot the teeth 3rd extrude 4th use flex/ twist to rotate ur teeth!
be happy :)