Not enough precision for threading. Even if you could do a PWM to pulse
convertor it will not work. You will need a true encoder, home made or not.
More, it will be simpler.
For threading you don't only need the exact speed of the spindle, but his
absolute position too with a good accuracy. Can only be done with an encoder
with index + eventually other pulses for low or medium speed applications.
Olivier.
