This 4 cm long nozzle should be printable by most 3d printers with decent cooling. I recommend printing it in the orientation as provided with supports touching the buildplate. The thread should be printable without supports that way. 

Had alot of fun designing this nozzle in fusion360 as one of my first projects. The thread isnt realistic, since i scaled it up a bit to be printable on an fdm machine. Other than that the dimensions should be decently correct if you were to scale it down to a 0.4 nozzle. 

Display your 3d printing hobby with this cool chopstick rest :D