As for my jack-making practice, I use two jigs for making the body, one
for the axle hole and one for the spring anchor; everything else is done
with depth stops on the (General) table saw and band saw. The tongue
requires three jigs, one for milling the back profile, one for drilling
the axle hole and one for punching the plectrum mortice. All the other
work on the tongues is done with depth stops or by hand.
It is mindless work after a while. I tend to put on headphones and
listen to Mozart quartets. Perhaps I'll try an audio book one of these