I am unconvinced by this theory.

1) If microscopic ratchet teeth are created to cause the bolt to
self-tighten, wouldn't they be destroyed when the god-awful tight bolt is
broken loose? The bolt at least should be specified as a "use once" item,
regardless of how the mating threads in the crank fare.

2) In order to tighten, the bolt will have to move with respect to the
pulley. That means the washer must have similar ratcheting action, and on a
similar microscopic level to allow the ratchet to occur with miniscule
motion. That means if the washer is less than pristine and is reused the
bolt won't self-tighten.

3) The forces are downright outrageous. In round numbers, if the washer
diameter is 1/2 inch and the bolt thread diameter is 1/4 inch, to tighten
past the 200 ft-lb mark the bolt head has to experience 5000 pounds force
from one side to the other, or 10000 pounds force on one side relative to
the center. The equivalent force on the thread is double that.

4) If there is significant motion of the pulley relative to the crank, the
mating surfaces will wallow out. We see it often enough with splined drive
axles that are insufficiently torqued.

Altogether, it doesn't add up. Torsional forces between the pulley and crank
must act unidirectionally on the bolt, with several tons of force being
transferred through both sides of the washer and without damaging the pulley
or crank mating surfaces, with enough movement to materially tighten the
bolt. The theorized ratchet mechanism has to operate on a microscopic basis,
not be damaged in removal, and to allow effortless unthreading when the bolt
is broken loose. It must work over a wide range of lubrication, including a
penetrant oil film or being cleaned with brake cleaner. I'm glad I haven't
been asked to design something like that, particularly if I could just
specify tightening to a different torque in the first place.

Mike

http://square.cjb.cc/bolts.htm

  "Self Tightening Bolts theory.
  Warning: this page is only a theory, not a fact."

That's a good description.

Could someone please explain what self-tightening and
self-locking bolts are and give examples. The author may
have the latter in mind.

  "Figure 4.1 This picture explains the great inertia and
  centrifugal force"

  "When ever there is a difference in inertial force (as
  pointed out with the arrows) the pulley will move. Not
  180-ft-lb torque can hold the pulley still."

I wonder what this is about.