I read some explanations of precession; this side for example summarizes briefly almost all what I have understood so far.
But one thing bothers me: Following all this formulas, the precession velocity is constant as long as the external torque is applied constantly. So let there be a spinning disk without external torque (so no precession, the rotations axis keeps its direction). If I now start to apply some constant torque to change the rotation axis, does the precession velocity jump instantaneously to the calculated, constant value? Is there no "precession acceleration phase" or something?