In my wooden screw making efforts a “Eureka!” moment was the realization that the thread cutting tool can be made of two rectangular blanks clamped together to form a “vee” cutter. The material is High Speed Steel M2 lathe cutter blanks. The two part cutter is easier to make and easier to sharpen.
Here you can see a cut being made.
The screw has been backed off a little to show the “vee” shaped shaving. Thinned raw linseed oil is applied to the screw while cutting the thread. This softens and lubricates the wood and helps the cutter stay sharp much longer.