Another way to cut tapered threads would be with a hand held thread chaser, an under used bit of kit but useful all the same. They give a full form thread, that is to say they cut peaks and troughs, and they are good for making fine adjustments to machine cut threads as well.
Thread chasers, for those who don't know them, are the opposite of "single point threading" in that they cut several threads at once. They are available in machine and hand held varieties.
A certain amount of practise is need to cut a completely new thread but if wood turners can do it, so can we.
Ned